I'm using a SLES12 SP2 with SUMA 3
Unfortunately I do not find any special error messages in logs (system log, postfix log and taskomatic log)
Postfix logs do not find send attempts (if I try by mail command it works).
The problem is that it all seems to work properly but I do not understand where it hangs.
Unfortunately, as the Suse has said, emails can only be sent by SUMA automatically so I can not make test submissions from it.
In fact there is the ability to enable email sending even when the taskomatic is restarted. Well, I've tried it many times but nothing happens.
I'll try with a tcpdump to see if I can find something.

Thank you