Forum Discussion
Not receiving emails from O365/Outlook.com companies with Barracuda email security
Hello, Have an odd email delivery issue, which was working up until about 5/27. We are no longer receiving emails from companies using O365/Outlook.com and Barracuda email security it appears (b...
Hello bmerri19,
If the senders only see 2 hops in the NDR this sounds like it's the proxy configured on their mail server that's timing out.
Could you maybe post a NDR so we can have a look?
If the senders only see 2 hops in the NDR this sounds like it's the proxy configured on their mail server that's timing out.
Could you maybe post a NDR so we can have a look?
BemmelenPatrick Here are two from separate organizations:
As well as headers from when it was working in April/May,
and now no longer working:
It's just weird that is a handful of external organizations with O365/Barracuda all of the sudden emails don't arrive. Curious if something changed at the end of May on O365 or Barracuda?
-Brian
- Hi Brian,
Are you allowing both SMTP and ESMTP traffic from the outside? So ports 25 and 587?
And do you have a SonicWall that has a SSL certificate check possibility?
To me it looks like your firewall is blocking SMTP traffic with unsigned certificates as normal SMTP traffic is accepted but ESMTP is not.
It could be that the other side is using self signed certificates on the Barracuda...
