Exchange Server 2003 wont send emails

I have a client with Server 2003 SBS SP2 with Exchange 2003 installed.  Friday a.m. anyone at my client was able to send/receive emails without issue.  Friday afternoon, any email sent externally will leave the sent items in Outlook but would come back bounced a few days later (See attached PDF).  This morning, they started getting a new message: (See attached text file)

I have checked if the:
>ISP changed the static IP - they hadn't
>ISP blocked a port - they hadn't
>Domain was blacklisted - it wasn't
>I recently inherited this client from another IT company.  The previous IT company left 2 batch files on the server desktop: 1) Stop Exchange Service 2) Start Exchange Service.  Using these short-cuts, I stopped and restarted the service without any success.

Any assistance?
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Are these errors coming from multiple external domains or just this one in particular?

Are you receiving external email okay?
AustinnsAuthor Commented:
Any external email receives a bounce - eventually
External emails arrive quickly

FYI: there are about 10 email accounts on the domain that are having the issue
If you're receiving external email fine, it seems more like a DNS issue then.  Open up the Exchange System Console, expand Servers, expand the server that is sending the email outbound, expand protocols under that server, expand SMTP and right click on Default SMTP Server and select properties.  Go to the Deliver tab, and click the Advanced button.  Click Configure next to 'Configure external DNS servers'.  From here you can see the external DNS servers used to send outbound email.  Verify those are correct.

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AustinnsAuthor Commented:
Thank you for your help.  There was a legacy email account for their ISP that we did not know about.  We discovered that my client was flagged for spamming by the ISP and shut-down Friday.  We reset the password for the legacy account and updated the account settings.

I would have had difficulty finding these settings without your help.
glad i was able to assist!
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Windows Server 2003

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