When trying to add a new Netlify site, I could choose my GitHub organization and correctly see the repositories. When I selected a repository, I got an error which included this message: “This could be because the repository is empty or disabled”
Using Chrome dev tools, I saw that the Netlify site creation page was making a call to GitHub which resulted in 404.
This issue is that a recent branch had an ampersand “&” in the branch name, and Netlify was passing this as the value for the “ref” URL query parameter without escaping. Example:
I simply deleted that branch from GitHub and all is ok. Just wanted to bring this to light.