The database seems to have crashed a few times because the db-server ran out of memory. Unfortunately due to resource issues at Hetzner, we can't currently scale up the server.
For now we've limited the memory usage of Postgres so it shouldn't hit the limit again. We'll scale the server once Hetzner has resources available.
Again, sorry for the downtime.
@support it's almost a year I'm a member here and this is the first time something like this has happened.
I suppose Hetzner will provide eventually a permanent solution.