Not fully sure what the issue is, but all the tags files for containers aren't being populated.

https://registry.fedoraproject.org/repo/fedora-minimal/tags/ for example.

Indeed on sundries01, the file is 0 length:

-rwxr-xr-x. 1 root root 0 Jul 19 18:05 /var/lib/reg-server/static/repo/fedora-minimal/tags/index.html

I note that /srv/web/registry-signatures directory doesn't exist, and is empty on proxies.

Running reg for fedora-minimal shows:

[root@sundries01 reg-server][PROD-IAD2]# reg server -r registry.fedoraproject.org --once |& grep -i fedora-minimal
time="2020-07-19T18:05:59Z" level=info msg="generating static tags page for repo fedora-minimal"
time="2020-07-19T18:05:59Z" level=warning msg="generating tags template for repo \"fedora-minimal\" failed: getting v1 manifest for fedora-minimal:27 failed: missing signature key"

Also, there's some cron job runs of reg that have been failing lately. I am not sure if thats related or not:

creating index failed: getting catalog for registry.fedoraproject.org failed: Get https://registry.fedoraproject.org/v2/_catalog?last=gnome-contacts&n=100: http: non-successful
response (status=500 body="{\"errors\":[{\"code\":\"UNKNOWN\",\"message\":\"unknown
error\",\"detail\":{\"DriverName\":\"filesystem\",\"Enclosed\":{\"Op\":\"open\",\"Path\":\"/srv/registry/docker/registry/v2/repositories/filezilla\",\"Err\":24}}}]}\n")