How to troubleshoot Exchange Online NDR errors

Case



You need to troubleshoot an Exchange Online Non-Delivery Report (NDR) error.



Solution



Steps at high-level:



Analyze SMTP message headers by using the Exchange Online admin portal.



Identify if the NDR error has a known root cause and try to remediate the known root cause first.



If issue persists, check with the SMTP administrator of the recipient side.



Coming soon



References



https://docs.microsoft.com/en-us/exchange/mail-flow-best-practices/non-delivery-reports-in-exchange-online/non-delivery-reports-in-exchange-online


https://stefanos.cloud/kb/how-to-troubleshoot-exchange-online-ndr-errors/

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