SMTP no longer able to connect to send emails to external addresses

I know almost nothing about Exchange or outlook behind the GUI.  Our outsourced IT has recently upgraded our exchange server to 2010, and now we are experiancing a number of problems with external addresses. (POP,SMTP)

Could you give me some suggestions to pass on to our External IT as to where to look as to why my automated SMTP send that worked perfectly with the last verion of the Exchange Server is no longer working with the upgraded version 2010?

All automated SMTP emails that I send to internal addresses only works fine.  But anything that contains ANY external email addresses fails for all recipents, 550 unable to relay.  I had been using as the SMTP server, and I am using authentication.

I'm assuming the authentication must still be valid or nothing would get through.
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I would be very much considering why you pay an external IT company who cannot solve this for you after an upgrade but still... My first thing to check would be the SMTP connector and make sure its setup correctly and to allow the new server to send and not an old server name...
penguinjasConnect With a Mentor Commented:
Ask them to check and see if the computer sending the automated SMTP emails is listed as an allowed SMTP relay in the Exchange 2010 Management Console.  They can find it under the hub transport role under the tab Receive Connectors.
ScriptAddictAuthor Commented:
Thanks for your help
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