Exchange gives Mailbox unknown or not accepting mail. 550 5.7.1 Unable to relay for error for new domain

I have exchange 2003 sp2 and added a new domain in the recipient policy.  I have three domains i accept email for.  The original 2 are fine.  The new one i just added gives me an error when i send email to a user i get  The message cannot be delivered to the following address. ---    Mailbox unknown or not accepting mail.
550 5.7.1 Unable to relay for

The user has an email account for them in AD and they can recieve mail from the other domains.  I have re-started the exchange box to "force" an recipient policy update and still get the same error

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Did you add the email address for the new domain to that user as well? If yes then try to add that email address once more. If you don't get an error the address is not registered in the system.
infranetsupportAuthor Commented:
All new emails with the new domain were created with the Recipient policy.  I have since take a few users, deleted the email manually and added it back manually with no luck..same error message
infranetsupportAuthor Commented:
Had to call Microsoft.  they found two versions of .NET framework.  They were not letting the new domain to be written to the metadata.  We made a change in the registry for one version of .NET, restarted IIS and exchange services and it worked!

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