12:22:23 PM: Failed during stage 'building site': Build script returned non-zero exit code: 2 (https://ntl.fyi/exit-code-2) Command failed with exit code 1: CI= npm run build

You need to

  1. add the build command
  2. check this guide on how to resolve the page not found error: [Support Guide] I’ve deployed my site but I still see "Page not found”