HTTP 503 ERROR trying to import repo with OAUTH2

I’m working with a private nodeJS repo and I imported it using OAUTH secret instead of SSH private key inside the package.json of am another project.
Often (not always) when I run the command:
npm install
of this project it remains stuck under my private repo and after a while I get this message:
npm http fetch GET 503 70502ms attempt #3 (cache skip)