E-Mail Reception problem

Since yesterday morning, I have not received any e-mails. I sent a test e-mail to my own @mac.com e-mail, and

it did not come through. I do have Internet reception, the problem seems to be only in receiving e-mails, the outgoing

e-mails seem to be going through okay.

Any tips to fix this or to find out what is happening? I don't believe it is that the inbox is too full. I moved hundreds of

messages into a folder to get them out of the inbox.

Thanks in advance; this is FRUSTRATING!

Just in case '06 iMac running 10.4.11 OS system with Intel using the Mac mail, and I am also on the .me system.

No new e-mails have come into that folder, either.