I'm not familiar with Email Cloud Security from Symantec but need your expertise help.
We have customers and suppliers using Messagelab for in and out bound email.
From time to time we have problem with email coming from these domains as they are not using the MX record in correct order.
Our company have 3 entries in the MX record, two of the records are for backup purpose. Our backup mail server has more resticitive security settings so mail are sometimes bouncing back to sender. We really would like to have all email going through the primary mailserver and have the sending server to use the MX record priority.
When talking to our customers and suppliers, they say they don't have any problem with their emial.
Anyone that have seen similar issues or have ideas what is causing email from Messagelab not using the MX priority.
Might ask the company that uses Symantec email security cloud, to use the Track And Trace function at ClientNet.
Look for details on the email with a problem.
They might see some details about what is occuring.
For example, does Symantec try the first MX host, but maybe has problems connecting.
Just an idea.