What this error means

Module not found: Can't resolve means the build or deployment failed in a clean automation environment. The cause is usually runtime version, lockfile state, secrets, project root, or deploy permissions.

Common causes

  • Import path case differs from the actual filename
  • Dependency is listed in the wrong package.json section
  • Build root points to the wrong directory
  • Generated files are not created before the build

Copy-paste commands

Check local Node version

node --version
npm --version

Reproduce a clean install

rm -rf node_modules
npm ci

Run the production build locally

npm run build

Check GitHub SSH from a runner-like shell

ssh -T git@github.com

Quick fixes

  1. Open the failed log and find the first error line above the stack trace.
  2. Fix import paths exactly, commit missing files, and verify Vercel uses the intended project root.
  3. Check Node version, working directory, lockfile state, and required secrets.
  4. Rerun the job only after committing the config or lockfile change.

Step-by-step troubleshooting

  1. Find the first log line containing Module not found: Can't resolve.
  2. Check the job Node version and package manager command.
  3. Verify secrets are available for the event type; forked PRs often have restricted secrets.
  4. Compare the workflow working directory with the folder containing package.json.
  5. Run the same install and build commands locally from a clean checkout.

Platform-specific fixes

GitHub Actions

  • Use actions/setup-node for the intended Node version and keep package-lock.json committed for npm ci.

Vercel

  • Check the configured project root, build command, output directory, and environment variables in the Vercel project settings.

Real-world fixes

  • If the lockfile error appears only in CI, regenerate and commit the lockfile instead of switching to npm install in CI.
  • If deploy keys fail, confirm the public key is attached to the target repository and the private key secret keeps newlines intact.
  • Fix import paths exactly, commit missing files, and verify Vercel uses the intended project root.

How to prevent it

  • Keep workflow runtime versions explicit.
  • Commit lockfiles and generated config needed at build time.
  • Add a small CI job that runs the same build command before deploy.