I also appear to be having this problem right now. Looking at the javascript console I see 400 (BAD REQUEST) on a DELETE request. I have tried Chrome, Edge, Safari & Firefox.
I should add this was a private repository created by a CI/CD pipeline.
I have also discovered just now that if I make the repository public and then delete it, this works!
Building and pushing a repository from the command-line also results in the same behaviour, so ruling out the CI/CD limited read+write access token.
The main frustration with this is that while I can push, I cannot pull the repository, or delete it. Attempts to pull the repository give an “access denied” message.
A possible workaround is changing the new repository from “private” to “public” and then back to “private”. The issue then seems to go away (at least so far). This isn’t very good, but something about permissions seems to be the problem, when initially creating private repositories currently. This was working fine until today - though I probably haven’t created a new repository for a while.