Can not send email

Question

Can not send email

Anonymous

I have a problem sending emails to external users. I am currently using my company domain and have created mailboxes. However, all emails I send from the newly created mailbox to domains outside the organization are marked with the error “can not send this item”. I did not type.

Is it because of an error in verifying dkim or spf or because of a conflict with mail rules?

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Answer 1

Hi Limal,

Thank you for posting your question in the Microsoft Q&A forum.

Based on your inquiry, we understand that you have received an announcement about cannot send mail to external user. We will be glad to assist you in this part. According to your issue, I believe this could be cautioned by the domain associated with the new mailbox isn't verified or added as an accepted domain in Microsoft 365, emails to external domains may fail.

You can:

Go to Admin Center ->Settings > Domains.
Select the domain which you create mailbox and ensure its status is Healthy (DNS records like TXT and MX are correctly set).
If not, you might need to set up the domain again to meet the necessary requirements.
Add a domain to Microsoft 365 - Microsoft 365 admin | Microsoft Learn

You also need to ensure the domain is listed as an Accepted Domain in the Exchange Admin Center:

Go to Exchange Admin Center
Mailflow -> Accepted domains Manage accepted domains in Exchange Online | Microsoft Learn

If you need further assistance, please let us know.

For troubleshoot it more effectively, could you check MX, SPF, DKIM, and DMARC records via NS Lookup tool.

Additionally, could you also check the mail flow rules to make sure no rule blocking send email to external recipients? Manage mail flow rules in Exchange Online | Microsoft Learn

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