General :: Ubuntu Mailser Not Receiving Emails

I recently setup a mailserver on ubuntu server. I am able to send emails correctly. However, no emails show up when sent to me on this server. I can send emails to myself on the server but not outside email like yahoo.com or gmail or any other emails can reach me. My MX and A record appear to have been set up correctly. My router seems to receive hits when I receive emails. When I check the logs of the router it tells me that there was a remote attempt to send traffic to the router forwarded to the server but I don't see this traffic in any mailbox. When I do pingability.com for my site, I get the following error message:Error There was a problem while talking with the mail server. Got 'Socket Timeout Exception: connect timed out' So somehow, the email traffic seems to get to my router and my router appears to forward it to my server but it does timeout.