I have a user, user@domaina.com and an alias set as user@domainb.com. This works fine over EWS, I can choose to send as either address (DKIM etc all set up).
As I can't currently send using EWS (https://github.com/grommunio/gromox/issues/102), I am trying using the web interface, but get the error "W-1643: rejecting submission of msgid e200050000000001h because its PR_SENT_REPRESENTING_ENTRYID does not reference a user in the local system".
Is there something I've missed to make zcore aware of the aliases? Other than the outgoing smtp url which I already have set in /etc/gromox/gromox.cfg I don't see anything else that would apply.