Sophos Blocking SMTP Outbound traffic

Hi,

we have a couple devices (like notifications from our Anti-Virus Server or Printers) that need to send Mails to Office 365.
I already created a Firewall Rule that allows traffic on the ports 25,465 and 587.
I also tried rules like "HOST" -> ANY -> ANY and it still does not work.
E-Mail Protection is deactivated.

Authentifcation with the external Mail Servers is of course required.

I tried other services (like our own external Mail Servers) and it does not work.
Interestingly the Sophos Notifications themselves work just fine.

I suspect that one of "the other" security mechanisms block the traffic from the LAN
We have a couple VLAN's

i tried this on XG / UTM and both block the traffic.

Does any one have suggestions since i ran out of ideas.

According to the Firewall log the traffic over 587 goes threw. i'm not sure if there is another sec mechanism of sophos that can block the traffic after passing the firewall?
if no the problem could be microsoft or the answer from the ms servers. im not sure atm.