Use NSLOOKUP and check the zone for setup similar to this:
"ole.as 86400 IN MX 10 cobalt3.nsn.no
mail.ole.as 86400 IN CNAME cobalt3.nsn.no"
The CNAME record causes sendmail to fail, even though mail.ole.as is NOT listed as an MX host. Change to:
"ole.as 86400 IN MX 10 cobalt3.nsn.no
mail.ole.as 86400 IN A 195.159.62.37"