Hi Stephan,
You are running a Tor relay, which is great: http://rougmnvswfsmd4dq.onion/rs.html#details/17732866AF67A4716E0876E5F5845C...
But that Tor version is obsolete, and because of old bugs, we will soon cut relays running those versions out of the network. Please consider upgrading!
You can find Tor packages for your distro / OS here: https://trac.torproject.org/projects/tor/wiki/TorRelayGuide#Platformspecific...
Ideally you will switch to keeping up with our stable releases, but if you need a stable that is especially stable, the Tor 0.3.5 branch will be maintained until Feb 2022: https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkTeam/CoreTorR... and you can see the lifetimes of other Tor versions on that table too.
Let us know if we can do anything to make the process easier.
And lastly, I am cc'ing the new network health mailing list (which has public archives), to help us stay synced: https://trac.torproject.org/projects/tor/wiki/org/teams/NetworkHealthTeam
Thanks! --Roger