Hi @admin admin213 , according to your information above, all users in your organization can send messages properly but not receiving(both internal and external), we may refer to the below several points to troubleshoot this issue:
- Please check the message tracking log to get the detailed information about the whole message delivery process. Search message tracking logs
- Make sure the services used in Exchange mailflow are running properly, check the configuration of your DNS records, also try using the ExRCA tool to test the mailflow of inbound SMTP Email
- Verify if the disk is almost full. If yes, free some space and then check the result again.
You could check if there is any event logs of Back Pressure which will lead to the message delay as well. Like eventid 15004,15006,15007... - You could also check if there is any other related error logs recorded in the event viewer, share them here for further troubleshooting.
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