Inbound E-Mail not received from certain addresses

[pborm]

Hi there. I have the weirdest problem. I've just installed Zimbra for the first time for my organization. I do have to say I'm quite impressed. Anyway, I was able to send and receive to a good dozen or so other addresses except for my other personal e-mail from another provider. I'm able to send to that address, but when I reply back I get the following error...

The mail server could not deliver mail to admin@xyz.ca. The account or
domain may not exist, they may be blacklisted, or missing the proper dns
entries.

I have the domain registered with godaddy and I set the MX records to the following...

MX (Mail Exchange)
Priority Host Goes To TTL Actions
0 @ XX.XXX.XXX.XXX 1 Hour

When I do a check on the MX record inside of the Zimbra admin panel I get the following...

Domain is configured to use SMTP host: xyz.ca. None of the MX records match this name. Found the following MX records:
0 XX.XXX.XXX.XXX.

I did verify that xyz.ca resolves to the IP address, and since the other mail providers seem to find it I'm at a loss. Any ideas on what I can try?

[Dirk]

It looks like you need to have your reverse DNS entry set correctly. Many mail servers will block delivery to/from servers that have a mismatch.

For example, using Zimbra's own servers here:
Ping mail.zimbra.com gives mta02.zimbra.com at 207.126.229.144

the important part is what happens going the other way: ping -a 207.126.229.144 shows the dns entry of mta02.zimbra.com

[ArcaneMagus]

Another issue that you might be running into is it looks like you might have an IP address listed for your MX record. MX records should list a FQDN not an IP address.