@mko Your issue is this:
9:48:11 AM: $ npm run build
...
9:48:25 AM: Treating warnings as errors because process.env.CI = true.
9:48:25 AM: Most CI servers set it automatically.
...
9:48:25 AM: [eslint]
9:48:25 AM: src/PortfolioContainer/AboutMe/AboutMe.js
9:48:25 AM: Line 12:9: 'fadeInSubscription' is assigned a value but never used no-unused-vars
9:48:25 AM: src/PortfolioContainer/Home/Header/Header.js
9:48:25 AM: Line 22:9: 'currentScreenSubscription' is assigned a value but never used no-unused-vars
9:48:25 AM: Line 42:9: 'classes' is assigned a value but never used no-unused-vars
9:48:25 AM: src/PortfolioContainer/MyWork/MyWork.js
9:48:25 AM: Line 13:9: 'fadeInSubscription' is assigned a value but never used no-unused-vars
The default is that warnings be treated as errors and your build is throwing warnings.
If the build encounters an error it will fail.
If you don’t want this behavior, you can set CI to false, the easiest way for you to do this will be to change your Build command from npm run build to CI= npm run build