sendmail cannot resolve domain

[Gary Reid]

Hi

anyone had any problems with sendmail on VS's - we have one out 4 on a host
which just gets

Sender domain must resolve

on domains which do resolve and which other VS's on the same machine are
dealing with fine - even in the VS with problems nslookup successfully
resolves the domains. Don't really want to comment out the rule in
sendmail.cf.... anyone any ideas?

Gary