MX Record points to unknown SMTP host?

[jhgarrison]

trafficstars

Tried to send email to [email protected] but it bounced.

While you have a valid MX record in DNS, it points to a non-existent host:

[jhg@janus ~]$ dig rubberduckvba.com mx ; <<>> DiG 9.11.36-RedHat-9.11.36-4.el8 <<>> rubberduckvba.com mx ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48653 ;; QUESTION SECTION: ;rubberduckvba.com. IN MX ;; ANSWER SECTION: rubberduckvba.com. 3312 IN MX 0 rubberduckvba-com.mail.protection.outlook.com.

[jhg@janus ~]$ dig rubberduckvba-com.mail.protection.outlook.com ; <<>> DiG 9.11.36-RedHat-9.11.36-4.el8 <<>> rubberduckvba-com.mail.protection.outlook.com ;; QUESTION SECTION: ;rubberduckvba-com.mail.protection.outlook.com. IN A

Also

[jhg@janus ~]$ nslookup @8.8.8.8 rubberduckvba-com.mail.protection.outlook.com nslookup: couldn't get address for 'rubberduckvba-com.mail.protection.outlook.com': not found [jhg@janus ~]$ nslookup @1.1.1.1 rubberduckvba-com.mail.protection.outlook.com nslookup: couldn't get address for 'rubberduckvba-com.mail.protection.outlook.com': not found