Cause there’s something wrong in FROM address, the mails which cannot be sent are queued in outbound queue, how to clear the outbound queue?
You can cancel pending tasks running
./bin/worker (from the server’s phabricator dir). use
./bin/worker help to see details.
Each outbound email is a pending task, so you can just cancel all pending email tasks.
http://<your install>/daemons/ to see pending/failing tasks.
Or fix the problem, I guess, and then old emails will start to go out.