NDR Reports Generated to Senders after DKIM and DMARC Created

Some (thankfully, not all) senders’ inbound emails are generating an NDR 550 5.1.10 that says the recipient’s address wasn’t found and later says Failed to deliver to Quarantine store. However, virtually all of them ARE delivered to the spam quarantine, and of course all the recipients’ addresses exist. The Microsoft configuration tester saya the configuration is correct, so what’s going wrong here? It’s alarming to the sender and to my recipients and I can’t find a thing on how to stop these errors from being generated. Has anyone else experienced this? How did you resolve it? Thanks so much for any help!

Hi SuperRed,

Configuring DKIM or DMARC would not cause the permanent error you are experiencing. However, it could be related to the DMARC policy depending on the enforcement in place. If you are at “none” then this is unlikely. That being said, for the messages being treated as spam, if any, Microsoft adds useful headers in order to help determine the cause of a message’s disposition. More information can be seen here.

This may be a good place to begin.

Will do! Thank you SO much for your help.