Microsoft 365 Business Basic

Copper Contributor

Hello guys,


I created two emails that initially I intend to use in the future with the application I am developing. These emails are part of a domain I have and I followed all the instructions to register them in M365 start basic. After that, I registered the two emails in Outlook, without problems.


What's happening: I can send emails to any mailbox. The problem is that whoever receives these emails cannot reply. This is the message they receive:


Mail delivery failed: returning message to sender This message was created automatically by mail delivery software.

The message that you felt could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: Email address removed (generated from Email address removed)


There is no one at this address and this is the content that is attached to the email:


Reporting-MTA: dns; Action: failed Final-Recipient: rfc822;Email address removed Status: 5.0.0


Could anyone help please?






3 Replies
Did you update the MX record for the domain to point to O365? Step #2 here:
Hi Vasil,

thanks for your response. I'm checking this and will update you.

Hi Vasil,

despite some health issues I had, I was able to check your suggestion and everything is working perfectly.

Thanks again and all the best!!!