I tried all, even rebuilt my email accounts and it didn't work...

I might have a specific case.

I use my computer both at home and at work.

At home it works fine.

At work it only sends emails.

Due to company standards I got to be connected to its network and server, and need to use a different mailbox to the one I use at home, since the mailbox server is the company one (I'm not exactly a pro on this matter, but I suppose you got the rationale of the situation).

Well, I triplechecked all the mail box specifications, I did use the mail doctor and it says that everything is fine with my email accounts. I tried to rebuild my mail boxes and still it didn't work.

What else can I do?

Might that be a Mail bug?