yarn patch-package packagename fails with 401 Unauthorized, npm run patch-package doesn't help either.

This usually happens when your company self-hosts packages, in our case with JFrog artifactory, but it can be other registries.

When patch-package fails with 401 Unauthorized for private registries, even if your command line is configured with the Identity Token, you can run this instead:

npx patch-package packagename

Source: StackOverflow Answer