Error after yarn build completed operation

5:46:46 PM: Build ready to start
5:46:48 PM: build-image version: c5b01a919d3e16af69445c5de0cacb49efbb1a23 (focal)
5:46:48 PM: build-image tag: v4.4.0
5:46:48 PM: buildbot version: 0ada244ab84a1759a70d6b2cfc27c9987b5c77ca
5:46:48 PM: Building without cache
5:46:48 PM: Starting to prepare the repo for build
5:46:49 PM: No cached dependencies found. Cloning fresh repo
5:46:49 PM: git clone https://github.com/jacopobonomi/cepiss_disabili_frontend
5:46:49 PM: Preparing Git Reference refs/heads/main
5:46:50 PM: Parsing package.json dependencies
5:46:51 PM: Starting build script
5:46:51 PM: Installing dependencies
5:46:51 PM: Python version set to 2.7
5:46:51 PM: Downloading and installing node v16.13.0...
5:46:52 PM: Downloading https://nodejs.org/dist/v16.13.0/node-v16.13.0-linux-x64.tar.xz...
5:46:52 PM: Computing checksum with sha256sum
5:46:52 PM: Checksums matched!
5:46:55 PM: Now using node v16.13.0 (npm v8.1.0)
5:46:55 PM: Started restoring cached build plugins
5:46:55 PM: Finished restoring cached build plugins
5:46:55 PM: Attempting ruby version 2.7.2, read from environment
5:46:57 PM: Using ruby version 2.7.2
5:46:57 PM: Using PHP version 8.0
5:46:57 PM: Started restoring cached yarn cache
5:46:57 PM: Finished restoring cached yarn cache
5:46:57 PM: Installing yarn at version 1.22.10
5:46:57 PM: Installing Yarn!
5:46:57 PM: > Downloading tarball...
5:46:57 PM: [1/2]: https://yarnpkg.com/downloads/1.22.10/yarn-v1.22.10.tar.gz --> /tmp/yarn.tar.gz.uFBSG1PPFV
5:46:57 PM:   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
5:46:57 PM:                                  Dload  Upload   Total   Spent    Left  Speed
5:46:57 PM:   0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
5:46:57 PM: 100    81  100    81    0     0    648      0 --:--:-- --:--:-- --:--:--   648
5:46:57 PM: 100    95  100    95    0     0    268      0 --:--:-- --:--:-- --:--:--   268
5:46:58 PM:   0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
5:46:58 PM: 100   626  100   626    0     0   1394      0 --:--:-- --:--:-- --:--:-- 23185
5:46:58 PM: 100 1215k  100 1215k    0     0  2194k      0 --:--:-- --:--:-- --:--:-- 2194k
5:46:58 PM: [2/2]: https://yarnpkg.com/downloads/1.22.10/yarn-v1.22.10.tar.gz.asc --> /tmp/yarn.tar.gz.uFBSG1PPFV.asc
5:46:58 PM:   % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
5:46:58 PM:                                  Dload  Upload   Total   Spent    Left  Speed
5:46:58 PM:   0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
5:46:58 PM: 100    85  100    85    0     0    858      0 --:--:-- --:--:-- --:--:--   858
5:46:58 PM: 100    99  100    99    0     0    761      0 --:--:-- --:--:-- --:--:--   761
5:46:58 PM: 100   630  100   630    0     0   4012      0 --:--:-- --:--:-- --:--:--  4012
5:46:58 PM: 100   832  100   832    0     0   3943      0 --:--:-- --:--:-- --:--:--  3943
5:46:58 PM: > Verifying integrity...
5:46:58 PM: gpg: Signature made Fri 02 Oct 2020 11:17:27 AM UTC
5:46:58 PM: gpg:                using RSA key 6D98490C6F1ACDDD448E45954F77679369475BAA
5:46:58 PM: gpg: Good signature from "Yarn Packaging <yarn@dan.cx>" [unknown]
5:46:58 PM: gpg: WARNING: This key is not certified with a trusted signature!
5:46:58 PM: gpg:          There is no indication that the signature belongs to the owner.
5:46:58 PM: Primary key fingerprint: 72EC F46A 56B4 AD39 C907  BBB7 1646 B01B 86E5 0310
5:46:58 PM:      Subkey fingerprint: 6D98 490C 6F1A CDDD 448E  4595 4F77 6793 6947 5BAA
5:46:58 PM: > GPG signature looks good
5:46:58 PM: > Extracting to ~/.yarn...
5:46:58 PM: > Adding to $PATH...
5:46:58 PM: > Successfully installed Yarn 1.22.10! Please open another terminal where the `yarn` command will now be available.
5:46:59 PM: No yarn workspaces detected
5:46:59 PM: Started restoring cached node modules
5:46:59 PM: Finished restoring cached node modules
5:46:59 PM: Installing NPM modules using Yarn version 1.22.10
5:47:00 PM: yarn install v1.22.10
5:47:00 PM: warning package-lock.json found. Your project contains lock files generated by tools other than Yarn. It is advised not to mix package managers in order to avoid resolution inconsistencies caused by unsynchronized lock files. To clear this warning, remove package-lock.json.
5:47:00 PM: [1/4] Resolving packages...
5:47:01 PM: [2/4] Fetching packages...
5:47:26 PM: info fsevents@2.3.2: The platform "linux" is incompatible with this module.
5:47:26 PM: info "fsevents@2.3.2" is an optional dependency and failed compatibility check. Excluding it from installation.
5:47:26 PM: info fsevents@1.2.13: The platform "linux" is incompatible with this module.
5:47:26 PM: info "fsevents@1.2.13" is an optional dependency and failed compatibility check. Excluding it from installation.
5:47:26 PM: [3/4] Linking dependencies...
5:47:26 PM: warning "@craco/craco > @endemolshinegroup/cosmiconfig-typescript-loader > ts-node@9.1.1" has unmet peer dependency "typescript@>=2.7".
5:47:26 PM: warning " > @testing-library/user-event@13.5.0" has unmet peer dependency "@testing-library/dom@>=7.21.4".
5:47:26 PM: warning "react-scripts > @typescript-eslint/eslint-plugin > tsutils@3.21.0" has unmet peer dependency "typescript@>=2.8.0 || >= 3.2.0-dev || >= 3.3.0-dev || >= 3.4.0-dev || >= 3.5.0-dev || >= 3.6.0-dev || >= 3.6.0-beta || >= 3.7.0-dev || >= 3.7.0-beta".
5:47:40 PM: [4/4] Building fresh packages...
5:47:42 PM: Done in 42.74s.
5:47:42 PM: NPM modules installed using Yarn
5:47:43 PM: Started restoring cached go cache
5:47:43 PM: Finished restoring cached go cache
5:47:43 PM: go version go1.16.5 linux/amd64
5:47:43 PM: go version go1.16.5 linux/amd64
5:47:43 PM: Installing missing commands
5:47:43 PM: Verify run directory
5:47:44 PM: ​
5:47:44 PM: ────────────────────────────────────────────────────────────────
5:47:44 PM:   Netlify Build                                                 
5:47:44 PM: ────────────────────────────────────────────────────────────────
5:47:44 PM: ​
5:47:44 PM: ❯ Version
5:47:44 PM:   @netlify/build 18.19.2
5:47:44 PM: ​
5:47:44 PM: ❯ Flags
5:47:44 PM:   baseRelDir: true
5:47:44 PM:   buildId: 617c17666961c523f772be20
5:47:44 PM:   deployId: 617c17666961c523f772be22
5:47:44 PM: ​
5:47:44 PM: ❯ Current directory
5:47:44 PM:   /opt/build/repo
5:47:44 PM: ​
5:47:44 PM: ❯ Config file
5:47:44 PM:   No config file was defined: using default values.
5:47:44 PM: ​
5:47:44 PM: ❯ Context
5:47:44 PM:   production
5:47:44 PM: ​
5:47:44 PM: ────────────────────────────────────────────────────────────────
5:47:44 PM:   1. Build command from Netlify app                             
5:47:44 PM: ────────────────────────────────────────────────────────────────
5:47:44 PM: ​
5:47:44 PM: $ yarn build
5:47:44 PM: yarn run v1.22.10
5:47:44 PM: $ craco build
5:47:45 PM: warn - As of Tailwind CSS v2.2, `lightBlue` has been renamed to `sky`.
5:47:45 PM: warn - Please update your color palette to eliminate this warning.
5:47:47 PM: Creating an optimized production build...
5:49:01 PM: 
5:49:01 PM: Treating warnings as errors because process.env.CI = true.
5:49:01 PM: Most CI servers set it automatically.
5:49:01 PM: 
5:49:01 PM: Failed to compile.
5:49:01 PM: 
5:49:01 PM: src/pages/Campaigns.js
5:49:01 PM:   Line 12:65:   'notify_error' is defined but never used                                                                           no-unused-vars
5:49:01 PM:   Line 65:126:  Expected '!==' and instead saw '!='                                                                                eqeqeq
5:49:01 PM:   Line 74:23:   Expected '===' and instead saw '=='                                                                                eqeqeq
5:49:01 PM:   Line 87:23:   Expected '===' and instead saw '=='                                                                                eqeqeq
5:49:01 PM:   Line 125:33:  Array.prototype.map() expects a return value from arrow function                                                   array-callback-return
5:49:01 PM:   Line 133:6:   React Hook useEffect has a missing dependency: 'attivitaBackup'. Either include it or remove the dependency array  react-hooks/exhaustive-deps
5:49:01 PM: src/pages/Dashboard.js
5:49:01 PM:   Line 6:8:   'DashboardAvatars' is defined but never used  no-unused-vars
5:49:01 PM:   Line 7:8:   'FilterButton' is defined but never used      no-unused-vars
5:49:01 PM:   Line 8:8:   'Datepicker' is defined but never used        no-unused-vars
5:49:01 PM:   Line 10:8:  'DashboardCard02' is defined but never used   no-unused-vars
5:49:01 PM:   Line 11:8:  'DashboardCard03' is defined but never used   no-unused-vars
5:49:01 PM:   Line 12:8:  'DashboardCard04' is defined but never used   no-unused-vars
5:49:01 PM:   Line 13:8:  'DashboardCard05' is defined but never used   no-unused-vars
5:49:01 PM:   Line 14:8:  'DashboardCard06' is defined but never used   no-unused-vars
5:49:01 PM:   Line 15:8:  'DashboardCard07' is defined but never used   no-unused-vars
5:49:01 PM:   Line 16:8:  'DashboardCard08' is defined but never used   no-unused-vars
5:49:01 PM:   Line 17:8:  'DashboardCard09' is defined but never used   no-unused-vars
5:49:01 PM:   Line 19:8:  'DashboardCard11' is defined but never used   no-unused-vars
5:49:01 PM: src/pages/Orders.js
5:49:01 PM:   Line 5:8:      'DeleteButton' is defined but never used                                                                                                                                                                                                                                                                                                                                                                       no-unused-vars
5:49:01 PM:   Line 6:8:      'DateSelect' is defined but never used                                                                                                                                                                                                                                                                                                                                                                         no-unused-vars
5:49:01 PM:   Line 7:8:      'FilterButton' is defined but never used                                                                                                                                                                                                                                                                                                                                                                       no-unused-vars
5:49:01 PM:   Line 9:8:      'PaginationClassic' is defined but never used                                                                                                                                                                                                                                                                                                                                                                  no-unused-vars
5:49:01 PM:   Line 11:19:    'useLocation' is defined but never used                                                                                                                                                                                                                                                                                                                                                                        no-unused-vars
5:49:01 PM:   Line 14:8:     'Select' is defined but never used                                                                                                                                                                                                                                                                                                                                                                             no-unused-vars
5:49:01 PM:   Line 14:18:    'components' is defined but never used                                                                                                                                                                                                                                                                                                                                                                         no-unused-vars
5:49:01 PM:   Line 15:26:    'notify_loading' is defined but never used                                                                                                                                                                                                                                                                                                                                                                     no-unused-vars
5:49:01 PM:   Line 15:42:    'notify_loading_finish' is defined but never used                                                                                                                                                                                                                                                                                                                                                              no-unused-vars
5:49:01 PM:   Line 51:10:    'nome' is assigned a value but never used                                                                                                                                                                                                                                                                                                                                                                      no-unused-vars
5:49:01 PM:   Line 51:16:    'setNome' is assigned a value but never used                                                                                                                                                                                                                                                                                                                                                                   no-unused-vars
5:49:01 PM:   Line 68:21:    Expected '===' and instead saw '=='                                                                                                                                                                                                                                                                                                                                                                            eqeqeq
5:49:01 PM:   Line 77:77:    Expected '===' and instead saw '=='                                                                                                                                                                                                                                                                                                                                                                            eqeqeq
5:49:01 PM:   Line 88:13:    Effect callbacks are synchronous to prevent race conditions. Put the async function inside:
5:49:01 PM: useEffect(() => {
5:49:01 PM:   async function fetchData() {
5:49:01 PM:     // You can await here
5:49:01 PM:     const response = await MyAPI.getData(someId);
5:49:01 PM:     // ...
5:49:01 PM:   }
5:49:01 PM:   fetchData();
5:49:01 PM: }, [someId]); // Or [] if effect doesn't need props or state
5:49:01 PM: Learn more about data fetching with Hooks: https://reactjs.org/link/hooks-data-fetching  react-hooks/exhaustive-deps
5:49:01 PM:   Line 97:89:    Expected '===' and instead saw '=='                                                                                                                                                                                                                                                                                                                                                                            eqeqeq
5:49:01 PM:   Line 103:6:    React Hook useEffect has a missing dependency: 'registroSelected'. Either include it or remove the dependency array                                                                                                                                                                                                                                                                                            react-hooks/exhaustive-deps
5:49:01 PM:   Line 105:10:   'selectedItems' is assigned a value but never used                                                                                                                                                                                                                                                                                                                                                             no-unused-vars
5:49:01 PM:   Line 196:123:  Expected '===' and instead saw '=='                                                                                                                                                                                                                                                                                                                                                                            eqeqeq
5:49:01 PM:   Line 199:118:  Expected '===' and instead saw '=='                                                                                                                                                                                                                                                                                                                                                                            eqeqeq
5:49:01 PM:   Line 201:168:  Expected '===' and instead saw '=='                                                                                                                                                                                                                                                                                                                                                                            eqeqeq
5:49:01 PM:   Line 201:198:  No duplicate props allowed                                                                                                                                                                                                                                                                                                                                                                                     react/jsx-no-duplicate-props
5:49:01 PM:   Line 203:123:  Expected '===' and instead saw '=='                                                                                                                                                                                                                                                                                                                                                                            eqeqeq
5:49:01 PM: src/pages/ResetPassword.js
5:49:01 PM:   Line 6:26:   'notify_loading' is defined but never used         no-unused-vars
5:49:01 PM:   Line 6:42:   'notify_loading_finish' is defined but never used  no-unused-vars
5:49:01 PM:   Line 12:18:  Expected '===' and instead saw '=='                eqeqeq
5:49:01 PM: src/pages/Settings.js
5:49:01 PM:   Line 12:9:  'updateImmagine' is assigned a value but never used  no-unused-vars
5:49:01 PM:   Line 14:9:  'result2' is assigned a value but never used         no-unused-vars
5:49:01 PM: src/pages/TeamTiles.js
5:49:01 PM:   Line 8:8:     'PaginationNumeric' is defined but never used                     no-unused-vars
5:49:01 PM:   Line 15:10:   'components' is defined but never used                            no-unused-vars
5:49:01 PM:   Line 28:10:   'PAISelected' is assigned a value but never used                  no-unused-vars
5:49:01 PM:   Line 35:10:   'schedaPazienteDefault' is assigned a value but never used        no-unused-vars
5:49:01 PM:   Line 35:33:   'setSchedaPazienteDefault' is assigned a value but never used     no-unused-vars
5:49:01 PM:   Line 46:10:   'result' is assigned a value but never used                       no-unused-vars
5:49:01 PM:   Line 118:9:   'insertPAI' is assigned a value but never used                    no-unused-vars
5:49:01 PM:   Line 162:44:  Array.prototype.map() expects a return value from arrow function  array-callback-return
5:49:01 PM:   Line 163:14:  Expected '===' and instead saw '=='                               eqeqeq
5:49:01 PM:   Line 608:84:  Expected '===' and instead saw '=='                               eqeqeq
5:49:01 PM:   Line 628:98:  Expected '===' and instead saw '=='                               eqeqeq
5:49:01 PM:   Line 632:49:  Expected '===' and instead saw '=='                               eqeqeq
5:49:01 PM:   Line 688:78:  Expected '===' and instead saw '=='                               eqeqeq
5:49:01 PM: src/partials/Header.js
5:49:01 PM:   Line 2:8:  'SearchModal' is defined but never used    no-unused-vars
5:49:01 PM:   Line 3:8:  'Notifications' is defined but never used  no-unused-vars
5:49:01 PM:   Line 4:8:  'Help' is defined but never used           no-unused-vars
5:49:01 PM: src/partials/Sidebar.js
5:49:01 PM:   Line 67:13:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
5:49:01 PM: src/partials/dashboard/DashboardCard01.js
5:49:01 PM:   Line 2:10:  'Link' is defined but never used      no-unused-vars
5:49:01 PM:   Line 4:8:   'Icon' is defined but never used      no-unused-vars
5:49:01 PM:   Line 5:8:   'EditMenu' is defined but never used  no-unused-vars
5:49:01 PM: src/partials/header/Help.js
5:49:01 PM:   Line 2:10:  'Link' is defined but never used        no-unused-vars
5:49:01 PM:   Line 3:8:   'Transition' is defined but never used  no-unused-vars
5:49:01 PM: src/partials/orders/OrdersTable.js
5:49:01 PM:   Line 4:10:  'notify_success' is defined but never used         no-unused-vars
5:49:01 PM:   Line 4:26:  'notify_loading' is defined but never used         no-unused-vars
5:49:01 PM:   Line 4:42:  'notify_loading_finish' is defined but never used  no-unused-vars
5:49:01 PM:   Line 4:65:  'notify_error' is defined but never used           no-unused-vars
5:49:01 PM: src/partials/orders/OrdersTableItem.js
5:49:01 PM:   Line 5:10:  'descriptionOpen' is assigned a value but never used     no-unused-vars
5:49:01 PM:   Line 5:27:  'setDescriptionOpen' is assigned a value but never used  no-unused-vars
5:49:01 PM:   Line 7:9:   'statusColor' is assigned a value but never used         no-unused-vars
5:49:01 PM:   Line 18:9:  'typeIcon' is assigned a value but never used            no-unused-vars
5:49:01 PM: src/partials/team/TeamTilesCard.js
5:49:01 PM:   Line 58:77:  Expected '===' and instead saw '=='  eqeqeq
5:49:01 PM: src/utils/Toast.js
5:49:01 PM:   Line 1:10:  'ToastContainer' is defined but never used  no-unused-vars
5:49:01 PM: error Command failed with exit code 1.
5:49:01 PM: info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
5:49:02 PM: ​
5:49:02 PM: ────────────────────────────────────────────────────────────────
5:49:02 PM:   "build.command" failed                                        
5:49:02 PM: ────────────────────────────────────────────────────────────────
5:49:02 PM: ​
5:49:02 PM:   Error message
5:49:02 PM:   Command failed with exit code 1: yarn build
5:49:02 PM: ​
5:49:02 PM:   Error location
5:49:02 PM:   In Build command from Netlify app:
5:49:02 PM:   yarn build
5:49:02 PM: ​
5:49:02 PM:   Resolved config
5:49:02 PM:   build:
5:49:02 PM:     command: yarn build
5:49:02 PM:     commandOrigin: ui
5:49:02 PM:     publish: /opt/build/repo/build
5:49:02 PM:     publishOrigin: ui
5:49:02 PM: Caching artifacts
5:49:02 PM: Started saving node modules
5:49:02 PM: Finished saving node modules
5:49:02 PM: Started saving build plugins
5:49:02 PM: Finished saving build plugins
5:49:02 PM: Started saving yarn cache
5:49:07 PM: Finished saving yarn cache
5:49:07 PM: Started saving pip cache
5:49:07 PM: Finished saving pip cache
5:49:07 PM: Started saving emacs cask dependencies
5:49:07 PM: Finished saving emacs cask dependencies
5:49:07 PM: Started saving maven dependencies
5:49:07 PM: Finished saving maven dependencies
5:49:07 PM: Started saving boot dependencies
5:49:07 PM: Finished saving boot dependencies
5:49:07 PM: Started saving rust rustup cache
5:49:07 PM: Finished saving rust rustup cache
5:49:07 PM: Started saving go dependencies
5:49:07 PM: Finished saving go dependencies
5:49:10 PM: Build failed due to a user error: Build script returned non-zero exit code: 2
5:49:10 PM: Creating deploy upload records
5:49:10 PM: Failing build: Failed to build site
5:49:10 PM: Failed during stage 'building site': Build script returned non-zero exit code: 2
5:49:10 PM: Finished processing build request in 2m21.789414366s

Change your build command to CI= yarn build.