I have an issue similar to the tickets 'Not Found' when trying to login with Netlify Identity and Netlify Identity - After Successful Authentication 'Not Found' Error Experienced. When trying to log in in our Netlify CMS, I see the “Not Found” pop-up over the page.
Looking into the network requests in Chrome, I see that the GET request to https://www.thetreeapp.org/.netlify/git/github/branches/develop returns an error code 404.
Our repository is private and organisation-owned. I changed the repository visibility to public as an experiment. With the public repository, everything works out fine and I am able to log in. When changed back to private, the log in ceases to work. Leaving the repository public is not an option, since the organisation would like to keep the code private.
Our Netlify CMS used to work fine for a long time with our private organisation-owned repository. We haven’t changed any Netlify-related settings recently, so this error is unexpected.
Please help me fix this issue. Let me know if any information is required for further debugging.