Hi @Cara Bereck Levy!
Thanks, let me know if you got something.. It's a strange behaviour.
Hi @AlexUT,
Yes, I was using Gmail account for the examples.
Looking after what you've said, I found some information on the web, but not exactly the same that's happening here.. There're few users with similar problems.
However, considering that the problem is external as you proposed (mail server, not Unistream), today I've tried with 2 other accounts (Zoho server), and the behave the same way Gmail account did.
So, I don't think that the problem is the mail server. Thanks!