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365 Postmaster Spam

klsphotos asked
Last Modified: 2018-02-06
Hello Experts,

Currently we have all of our Exchange accounts in 365.
I set myself to get the "postmaster" e-mails on undeliverable.

I am currently getting a lot of these?

Subject: Undeliverable: Your Flight Ticket Invoice 53518 - (our user)
Sender: ourcompany@onmicrosoft.com

Our we really sending these out?  I am concerned and not sure how or why our spam is increasing.

I found this question on the website and it's what is going on with us.  We have a spn record on our domain and they are coming frequent, so as of typing this, I"m unclear if there is anything or any other settings I can do to protect our domain?

Thank you for your help,

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