This issue can't be marked as solved by installing a whole other app because it doesn't fix the issue.
I'm facing the same issues. Updated to latest unraid version, updated all dockers - now gluetun cant ping github.com and it gets marked as unhealthy.
All other dockers works fine, has fine connection etc. Tried reinstalling gluetun by removing docker image and folder in appdata and installed again with minimum tweaking to settings - no luck getting outbound connection.