Strange DNS error in Sendmail

[Doug1953]

I have been running sendmail flawlessly for 15 years
for one host !! only i am getting consistant error
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V8
T1338666100
K1338827546
N98
P8766007
I0/92/12223607
MDeferred: Name server: mail.missionservices.ca.: host name lookup failure
Fwbs
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running
FreeBSD pop.lweb.ca 8.0-RELEASE FreeBSD 8.0-RELEASE #0: Sat Nov 21 15:48:17 UTC 2009
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debugs i tried
root@pop:/var/spool/mqueue# host -t mx mail.missionservices.ca
mail.missionservices.ca mail is handled by 10 mail.missionservices.ca.
root@pop:/var/spool/mqueue# host mail.missionservices.ca
mail.missionservices.ca has address 173.239.166.50
mail.missionservices.ca mail is handled by 10 mail.missionservices.ca.
root@pop:/var/spool/mqueue# telnet mail.missionservices.ca 25
Trying 173.239.166.50...
Connected to mail.missionservices.ca.
Escape character is '^]'.
220 mail.missionservices.ca Microsoft ESMTP MAIL Service, Version: 6.0.3790.4675 ready at Mon, 4 Jun 2012 12:40:15 -0400
quit
221 2.0.0 mail.missionservices.ca Service closing transmission channel
Connection closed by foreign host.
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i forced processing using
sendmail -q
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Any Ideas?

Doug Young