There are some reliability problems with Fedora Containers Registry. Users are often getting 503 Service Unavailable when downloading the content from registry.

1. I'm personally not able to update few days the Flatpak runtimes due to 503 errors.
2. Someone reported problems in Toolbox with CI due to 503 when downloading Toolbox images - https://github.com/containers/toolbox/pull/517#issuecomment-664829833
3. And there are other mentions of it around https://twitter.com/smartcity_lux/status/1291331505613090818 and https://discussion.fedoraproject.org/t/errors-when-trying-to-update-from-gnome-software/22287

Would it be possible to make it more reliable?

CC: @otaylor @feborges