Exchange grabbing POP3 emails

[dwg23]

Hello,
I am new to Exchange and inherited a Exchange 2000 server that was setup with the email adrs of @XYZ.com We also have a pop3 provider that was also setup as @XYZ.com.
Some of the POP3 adrs do not have an Exchange Adr.
This system has been working for quite a while just fine, but last week the Exchange server started grabbing all of the POP3 only messages that went out and then kicking them back because their was no xxx@XYZ.com at XYZ.com
I have no idea where to start looking.

 

[nobleman]

Sounds like your Dns changed. Can you verify that ?

CNE, MCSE, SCSA, CLS, CCSA, CCSE, CCNA, CCNP, MCNS, IP Telephony, CVoice, CSS1, CCIE and CISSP(prog)

Noble Computing, Inc.
Consulting
kshaffer@noblecomputing.com

 

[dwg23]

No, The DNS is unchanged.

 

[dwg23]

Found the problem, there is a setting that asks what to do with unresolved email adrs. it was blank, I set it to send to the POP 3 account and all is good.
Thanks for the help