Issue receiving emails from our internal servers

Hi,

For several days we have been presenting a problem that affects all our cPanel servers.

Strangely, the emails that we send from one of our platforms (IceWarp Merak) are not reaching the customer's inboxes.

Version of the cPanels (all have this problem)
CENTOS 7.6 vmware [premium1] v78.0.16

Then, looking at the logs of cPanels (mail logs), apparently the emails do arrive, but they are not visible in the client's inbox.



Even more strange, is that emails from external sources (gmail, hotmail, etc.) do arrive in the inbox.



I also did a test towards an older cPanel (WHM 11.30.8 (build 0) CENTOS 4.9 i686 vmware on dotweb-041) and the emails arrive immediately. So, it will be a version problem ?, since it is the only cPanel that is receiving mail, the others not.

There are no IP or spam blocks, all the IPs have been added to whitelist, so we discard a similar incident, and after doing a test with the old cPanel (which I mentioned earlier) the mail did arrive, so it must be the platform.

Any kind of additional information will be sent to you, thank you very much.

 

Hi, thanks for the answer ,

Below I send all the logs I could find, which corresponds to the mail flow:

1) Mail sent from our IceWarp platform, it comes out correctly without problems.



2) Mail goes through our SpamFirewall EFA, these are the logs (again without problems)


3) These are the logs found in our cPanel


Finally the mail is NOT seen in the inbox, ironically the emails from Gmail or Hotmail do enter correctly, this is a screenshot from the mailbox (this is very strange):



Thank you very much for the help!

 

In the end, it was a Networking problem on port 25, anyway, thank you very much for the prompt response!