Non-accepted domain report in the new Exchange admin center in Exchange Online

The Non-accepted domain report in the new Exchange admin center (new EAC) displays information about messages from your on-premises email organization where the sender's domain isn't configured as an accepted domain in your Microsoft 365 organization.

Microsoft 365 might throttle these messages if we have data to prove that the intent of these messages is malicious. Therefore, it's important for you to understand what's happening and to fix the issue.


By default, the report shows data for the last 7 days. If the report is empty, try changing the date range.

For permissions that are required to use this report, see Permissions required to view mail flow reports.

The overview section contains a chart that shows the number of messages sent per connector:

Overview of the Auto forwarded messages report.

The Non-Accepted domain details section contains the following information:

  • Date
  • Inbound connector name
  • Sender domain
  • Count
  • Sample messages: This field contains the internet message IDs (also known as the Client IDs) of a sample of the original messages. This value is stored in the Message-ID header field in the message header and is constant for the lifetime of the message.

To quickly filter the results, click Search Search icon. and start typing a value.

To filter the results by date range or connector name, use the boxes. You can specify a date range up to 90 days.

For more advanced filters that you can also save and use later, click Filter Filter icon. and select New filter. In the Custom filter flyout that appears, enter the following information:

  • Name your filter: Enter a unique name.

  • Click Add new clause. A clause contains the following elements that you need to enter:

    • Field: Select Date, Inbound connector, Sender domain, Count or Sample messages.

    • Operator: Select starts with or is.

    • Value: Enter the value you want to search for.

    You can click Add new clause as many times as you need. Multiple clauses use AND logic (<Clause1> AND <Clause2>...).

    To remove a clause, click Remove Remove icon.

    When you're finished, click Save. The new filter is automatically loaded, and the results are changed based on the filter. This is the same result as clicking Filter and selecting the customer filter from the list.

    To unload a existing filter (return to the default list), click Filter Active filter icon. and select Clear all filters.

Click Export to export the displayed results to a .csv file.

See also

For more information about other mail flow reports, see Mail flow reports in the new EAC.