Email issues adding new user Microsoft 365

Question

Current users emails are working. I added a new user to Microsoft 365. He gets interoffice email but when sending an external to him it bouncing back with this error.

----- The following addresses had permanent fatal errors ----- <

   550 invalid mailbox

I also have a MX record error "Invalid entry" I added the expected record that but still the same problem Any help would be appreciated.

The records we detected don't match all the expected values. We queried these nameservers for the records: ns43.domaincontrol.com, ns44.domaincontrol.com We didn't detect that you added new records to rhexco.com. Make sure the records you created at your host exactly match the records shown here. If they do, please wait for our system to detect the changes. This usually takes around 10 minutes, although some DNS hosting providers require up to 48 hours. Your domain must have a DNS record that matches the expected record for your ‎Microsoft 365‎ services to run smoothly. We recommend “copy and paste” to avoid errors.View step-by-step instructions to add ‎MX‎ DNS records Host NamePoints to address or ValuePriorityTTL

Expected record @ 

rhexco-com.mail.protection.outlook.com 

0 

1 Hour 

Invalid ******@rhexco.com.mx2-us.mailanyone.net201800

Invalid ******@rhexco.com.mx3-us.mailanyone.net301800

Invalid ******@rhexco.com.mx1-us.mailanyone.net101800

Answer 1

Hello RobertPetz82,

Thank you for posting this case in the Microsoft Community!

Based on your description, you have set up one email account in the Microsoft 365 admin center and could receive emails normally but when sending an external to him it bounces back with this error. I would like to cooperate with you to work on this case.

To clarify this case, as checked your NDR bounce message and the DNS records you added for the domain. It seems this case is related to DMARC Record not found which may cause this issue for email delivery to external receivers. You may check the MX Lookup analysis log from my side:

For my suggestion, you may check the following Microsoft article to add the DMARC Record completely and check if working.

SPF, DKIM, DMARC and Exchange Online

Use DMARC to validate email

If you need further assistance, please feel free to let me know, and I will keep assisting you.

Your understanding and patience will be appreciated.

Thank you!

Sincerely,

Microsoft Community

Answer 2

Hello RobertPetz82,

Thank you for your reply and I am very glad to know that this issue has been resolved by adding the expected MX record from your side!

If you think my reply is helpful, could you please submit feedback on my main reply? So that others who have similar issues can see it easily. Then they may check and perform the same steps to fix their issue with your efforts.

Thanks in advance!

Sincerely,

Microsoft Community

Answer 3

Thank you

I was able to solve the problem by changing the MX record with the GoDaddy account associate with the Domain name. I add the expected mx record and it solved the problem.

Answer 4

Dear RobertPetz82,

Good day! Thank you for posting to Microsoft Community. We are happy to help you.

At this very moment, we are looking into whether there could be a possible solution to this issue. We will get back to you as soon as we get any additional information about your query.

Your patience and cooperation are much appreciated.