Incorrect DNS info being returned when Reflexion trying to contact a domain from one Reflexions account, succeeds with another



I have Reflexions filtering outbound mail on two different email accounts. One account is able to successfully send email to the domain When I try to send through my other Reflexions account - the email goes into outbound quarantine as DEFERRED with the error - 'No Host Found'. We changed the nameservers for that domain 2 days ago and no other senders are having problems sending to it.

Seems like using cached DNS information. What does/how can I control what the (hosted) Reflexions service use to resolve the correct nameservers?