I tried to setup a replication task for my snapshots. From the GUI perspective everything worked. I waited a few days, but no snapshot ever showed up at my remote machine.
After manually adding debug lines in the autorepl.py script, the problem finally became apparent:
No ECDSA host key is known for <host> and you have requested strict checking. Host key verification failed.
I don't think I should need to manually add debug output to learn about this problem?
Instead it probably should generate an alert.
I assume the "Scan Host Key" WebGUI button (which I used earlier) should have actually fetched that key, but I guess that belongs into another issue.
Eventually fixed it by manually connecting with ssh one time where it asked me to add the key.