reattaching git repo not working

One of my project has git repo attached (tried even reattaching). Manually pressing “Deploy app” under Deployments UI works, but “auto-deploy on push” does not because of that error.

I think it is a bug from Fly.io side, any place I could get help? (my experience in migrating few project here has been quite painful so far)

Any info? I have tried to relink my project multiple times, nothing helps to get rid of this error. and 100% my project has access to repo because it is deploying it.