I don't really know how to properly describe this, but it's really annoying, so I'll try. Maybe it rings a bell.

Since a while I regularly can not send encrypted emails with Thunderbird, because enigmail's gpg-process hangs. If I kill the gpg-process (Thunderbird reports a failure in sending the message) and immediately try to send the message again, that usually works. Sometimes it takes two or three kill-gpg-and-send-again-loops. Sometimes even the first sending-attempt works.

I tried to debug this problem but didn't find any clue. I can't reproduce the problem, either. I did not change my setup deliberately. The only difference I noticed is that gpg-agent runs under systemd-supervision now.

For a while I tried to ignore this problem and wait for it to vanish as magically as it turned up, but apparently it is here to stay. Also, I spoke to one other person that experiences the same problem, so I now am more sure that my specific setup is not part of the problem.

Does this make any sense to you? Is there's any thing I can do or tell to clear this up?