OWA URL login works with Public IP but not Domain Name

I'm have a bit of an issue here.  I can log into my OWA externally using http://publicIP/exchange but not with http://mail.mydomain.com/exchange.  My mail.mydomain.com resolves fine to the public IP, however, I'm still unable to use the mail.mydomain in place of the public IP.  How can I get this to work like I want it to?
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Does the mail.mydomain bring you to a different site on your server?  It sounds like that HTTP header may be assigned to another website or web directory on your server.
KwodwoAuthor Commented:
No the message I get is "Oops! Internet Explorer could not find mail.usvigers.com"
Since you included the actual URL here I went ahead and tried it out and OWA comes up fine for me (I didn't try to log in obviously).  Are you testing from inside your network?  That error you received indicates that the DNS lookup failed.

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KwodwoAuthor Commented:
Yes I'm testing from inside.  Should an entry be added within the DNS lookup and exactly what?
KwodwoAuthor Commented:

I added the entry in my DNS lookup table and was able to pull you my OWA using the URL with my domain name, thanks much
No problem, glad to hear you got it resolved!
make sure mail.mydomain.com  command should be found on Public DNS  Server where you got Public IP
sooory no command but A record

make sure mail.mydomain.com  A record  should be found on Public DNS  Server where you got Public IP

check by nslookup
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