Hi experts,
I'm using Apex 20.2 and I'm having problems with emails in Prod environment after first activating it.
It's working fine in Test env and configuration is the same (ACL, smtp server, port, firewall is disabled, etc...)
Tested with telnet to port 25 that I can send correctly emails in the linux console.
But emails get stuck in the mail queue and I don't see any error or reason:

Can anybody please help?
Thanks,
Jose.