Cannot send email to accounts

Mail from our Exchange 2003 server to addreeses is returned with a 4.7.7 error. We host our own email but use Nuvox as our ISP. Have emailed AT&T for delisting twice. Each time, problem goes away for a week, and then returns. Have checked DSL reports and other sites and we are not blacklisted anywhere. Any guidance will be appreciated.
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How does your DNS record look on ? Any problems with your reverse dns record?
bhaadprAuthor Commented:
No problems were detected at
Are you using a static IP or routing mail through a smart host?
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bhaadprAuthor Commented:
Static IP
I also have SEVERAL clients complaining about this issue. Most are on Nuvox or a similar T1 provider in town. Anyone make any traction getting this fixed?
I have the exact same problem and I am using Nuvox also. I found this workaround for exchange 2003 that works for me. I just set it up today. The domains I could not send to were, and I called Nuvox and they said these ISP's probably have a range of Nuvox IP addresses blacklisted.

We use Nuvox.  We were able to sove this problem by sending an email to requsting to be removed from their block/abuse list.
I was able to work around this adding a second SMTP connector in Exchange. On the first one, the namespace is a wildcard, and the second one for Bellsouth only. I found out the real server host name of our mail server by doing a reverse lookup, and used the server's real fqdn ( Also remember to check the option that tells you to allow relaying to that namespace.

I hope this works for you.

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Email Protocols

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