I cant seem to get my mail server to communicate properly. I have DNS set up properly to run my websites and added the MX record, I think, properly. But I can receive email from Hotmail for example, but I can send back to it.

If you can receive emails, it means the MX records for your domain name are set up correctly. The outbound email sending is not related to DNS records of your domain name. You may need to check if your ISP blocks outbound port 25. If so, you can use Dynu's outbound relay service.

Thanks for the reply

That makes sense... but all testing shows that my ISP (ATT Uverse) isn't blocking port 25. telnet connection to my WAN IP at port 25 was replying with the appropriate response. But in an attempt to solve the issue I cause more of one. I deleted all of the DNS records I had related to mail and rebuilt them, thinking there was an error.

Now I have only an MX record Node is defined as mail. Hostname is defined as domain.com

And nothing works.

I also have the A and AAAA records. And normal port 80 functionality is doing fine.