Not receiving emails at all to the tenancy

Question

Hello there,

This tenancy is experiencing an issue wherein no emails are being received whatsoever, and all emails are resulting in varying bouncebacks when attempts are made to reach any users.

This is affecting all users.

facing issue in receiving emails from different senders from multiple domains
some email comes through fine and some don't some fails in first attempts but goes through when sent again
I am getting NDR: 550 5.4.1 Recipient address rejected. Access denied.
we updated the SPF record as well
TTL updated to 3600
I have disabled Vade for M365, disabled some transport rules. I also have disabled DBEB which I know is not a recommended setting.
The domain was set to Authoritative but still the same

Answer 1

550 5.4.1 Recipient address rejected. Access denied can mean a few things:
https://learn.microsoft.com/en-us/exchange/mail-flow-best-practices/non-delivery-reports-in-exchange-online/fix-error-code-550-5-4-1-in-exchange-online

I would walk through this doc and if you cant fix it, open a ticket with support. There is a link in the doc on how to do that

Answer 2

Hi @JustinMicheal-7973

I agree with Andy, you could firstly check the troubleshooting steps introduced in the official document to see if any help.
In addtion, you could also use the mxtoolbox and test the Inbound SMTP Email in ExRCA tool for your o365 tenant to get more information.

Waiting for your update here.

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