Office 365 group to receive external email

New Contributor

Hello all,


Lately I have been running into an issue with trying to email to an Office 365 group with an external email address. Even with the group having external email enabled, none of the email ecternally is coming through. Does anyone know how this can be fixed?


Thank you

11 Replies
Is this an issue happening Today? I'm asking this because EXO is experiencing a lot of problems least in my EMEA tenants and I think is also affecting e-mail
@Juan Carlos González Martin I'm experiencing the same problems today, including Possibly an EMEA wide issue.

This has been an issue from the start. We are trying to have this work and unable to do so. I am not sure that other steps have taken place to ensure external emails can send to Office 365 groups.

I think you need to follow your mail through to figure out what's happening. If you use Mail trace in exchange, find messages heading to that address and see what's happening to them.

When i look into Message trace on our Ironport I do see that the message was delievered. However when I look on message trace I do not see that anything came through. Is there something specific that needs to happen with Azure such as write back?

If you aren't seeing the messages at all in the Exchange Online message trace then they are being blocked elsewhere. Sounds like that IronPort might be up to something, surely it should tell you what it does with the message it receives?
Agree John, and problems are still there...I have several customer asking me what's happening with e-mail today...and my Microsoft accounts have not received any e-mail since a while

Can you do a message trace? Also, there have been some issues with Exchange online for Anti-x piece. Can you look at your spam configurations or quarantine emails? There have been issues going on with message quarantine for last few days with O365 tenant.

Hi Steve.  My IronPort is telling me that the message is queued for delivery. I believe that this is a mail flow issue. Comes in externally, hits IronPort and then once it hits exchange online, it is not routing correclty to on-prem. In my Delivery scop options for outbound to office 365 within EAC I am seeing there is only there. I am going to attempt to add along with routing mail through smart host, to see if this makes a difference.

On-prem? I would check everything works online, then there are a mass of pre-reqs and limitations for connecting to on-prem, see

@Tim Ihrig, please make sure, your Domain DNS settings are set up correctly, especially the MX-Record.


Go to: and check, if everything shows up ok.


One common problem in your case is caused, when a migration from Exchange on premises is not yet completed to Exchange Online and the DNS-MX record is still targeting the on premises Exchange, which does not know the MS 365 groups.


In that case, the sender might e.g. receive an e-mail error message containing:


autodiscover.[your e-mail domain] Mail delivery failed : returning message to sender



Kind Regards,