SMTP connection only fails with

My client's Exchange 2003 SP2 server fails SMTP connection to with the error

The connection was dropped by the remote host.

I force connection, it fails, all other email domain work but this one..
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Have you contacted nextel (sprint)
I believe they only allow you to use their smtp if you're on their network (ie using it from their phone).  If that's the case you should be able to use your ISPs smtp servers.
I think my answer was correct based on the info given. Is it?
JeffLundgrenAuthor Commented:
It was a duplex errors on the Router to the firewall and a new SPAM filter...

Thanks for the input.

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