Got it!
The problem was on a security tweak settings:
The message was not leaving the server and actually being sent due to one of configured Tweak Settings options. (RE: Mail sent by user nobody being discarded due to sender restrictions in WHM->Tweak Settings).In WHM, i navigate to Home >> Server Configuration >> Tweak Settings [ Mail ]. And in the option labeled "Prevent “nobody” from sending mail", i switch from On, to Off and it was solved.
Now i can get messages again!