Issue with build from merge request on gitlab.common-lisp.net

For ASDF, I have a CI workflow that builds the documentation.  This 
build fails on a merge request from another user.

Here's the job: 
https://gitlab.common-lisp.net/NicoSimoski/asdf/-/jobs/89084

Here's the relevant error message:

```
Getting source from Git repository 00:01
Fetching changes...
Initialized empty Git repository in /builds/NicoSimoski/asdf/.git/
Created fresh repository.
fatal: unable to access 
'https://gitlab.common-lisp.net/NicoSimoski/asdf.git/': The requested 
URL returned error: 500
```

Any idea why this would be happening?  Seems like the runner can't get 
at this fork, even though it's public.  I don't have any difficulty 
seeing https://gitlab.common-lisp.net/NicoSimoski/asdf

Is this something about GitLab runner permissions?

Or does his fork need to have GitLab actions enabled?

Thanks for any advice