I seem to be having the same problem. Making the repository in GitHub didn't help.

? For which GitHub repository would you like to set up a GitHub workflow? (format: user/repository)

!  The provided authorization cannot be used with this repository. If this repository is in an organization, did you remember to grant access?

i  Action required: Visit this URL to ensure access has been granted to the appropriate organization(s) for the Firebase CLI GitHub OAuth App:
https://github.com/settings/connections/applications/89cf50f02ac6aaed3484

√ For which GitHub repository would you like to set up a GitHub workflow? (format: user/repository)
kellywr10/repository1

Error: Request to https://api.github.com/repos/undefined had HTTP Error: 404, Not Found

I tried to "ensure access has been granted to the appropriate organizations" but a) I'm not sure who the appropriate organization is, and b) I'm not sure how to grant access (should I make it publicly visible? add collaborators? something else?).