ERR_NGROK_SHIP_GITHUB_REPOSITORY_NOT_FOUND: Repository REPO was not found on GitHub, or the ngrok GitHub app has no access to it - ngrok documentation

What does ERR_NGROK_SHIP_GITHUB_REPOSITORY_NOT_FOUND mean?

ngrok returns ERR_NGROK_SHIP_GITHUB_REPOSITORY_NOT_FOUND with this message:

Repository <REPO> was not found on GitHub, or the ngrok GitHub app has no access to it.

Where can I get more help with ERR_NGROK_SHIP_GITHUB_REPOSITORY_NOT_FOUND?

Email support@ngrok.com and include the error code.