I have a UCM-ETH03 running v2.23 on a UCM at v7.110 and Comfort at v7.140
I'm using smtp2go using mail.smtp2go.com and port 2525. I've proven my username/password via another application.
I have a static IP on the ETH03 with the correct gateway & mask & DNS so all is good I think.
I've got all alarms ticked for email 1 but I get no email for arm/disarm or dial test (or anything else). Problem is I don't think there's and diags on ETH03 or at the smtp2go end either.
Make sure that the user name and password for the SMTP account is correct as the ETH03 does notvalidate it.
This is what has worked for us (see screenshot attached)
It stopped sending emails for me recently. After I logged in on Comfigurator it started working again