Event ID - 4090

Event Id4090
DescriptionMail could not be delivered to <ip address> (for <domain name>). The destination server reported <error code> <description>; try again later. Delivery will be retried later.
Event InformationIt is complaining that there are no MX or A records for SourceDomain.com. The sender address has to be something that mail can be sent back to. So this is an issue related to DNS. This may happen whenever the destination DNS server try to resolve the senders address, which is enforced by SMTP server to avoid unsolicited mail.
Reference Links

Catch threats immediately

We work side-by-side with you to rapidly detect cyberthreats
and thwart attacks before they cause damage.

See what we caught

Did this information help you to resolve the problem?

Yes: My problem was resolved.
No: The information was not helpful / Partially helpful.