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