Try reconfiguring the Github app. Go to Railway account settings for that.

Already did

I have access to the repo as collaborator. However, I tried searched for the repo on Railway but I got No Repositories Found

move it to an organization, railway only supports deploying from the repo owners

Moving to organization works?

to github organzations yes

railway supports deploying from the repo owner

being a collaborator means you have access to it, not ownership

Got it thanks!