Recently an email delivery troubleshooter was added to the O365 Admin Center. That could be very useful for SD engineers or other admins, ( with the required permissiosn ), that doesn't access Exchange directly and would like to check some issues, ( before escalation, for example ).
From the Admin Center, if you go to Support - New Service Request and type "email delivery issue" the troubleshooter will come out:
I was testing the feature in a DEV tenant and found some issues/bugs. Please feel free to comment this post if you face the same behavior or maybe it's related only to my test tenant.
First, I created a Distribution Group in EXO, ( not allowing external senders ). Then I sent a message from an external test account to that DL and, of course, the message failed.
Once I tried the troubleshooter, it wasn't able to get the problem:
As you can see, it was not able to troubleshoot the issue and, something really strange, it identifies the external address as recipient, ( on the screenshots you can see that I set it as sender correctly ).
I thought maybe was a simple loading issue and refreshed the site to try again, but with the same result.
After that, it came to my mind that maybe the issue was that the troubleshooter was not able to identify DL's, ( which is bad, but anyway... ), and created a transport rule to block incoming messages to a test user mailbox.
Trying the troubleshooter from mailbox, ( external ), to mailbox, ( internal ), the result was exactly the same:
Finally tried sending internally another message to that blocked user, ( internal to internal ), and tested again. That worked fine!!
The result is very clear and describes exactly what's going wrong and how to fix it.
So, the tool could be very interesting but, from my perspective, it will need much more improvement before using it in a real business environment.
Let me know your thoughts ;)