Hi everyone, 

Need your help please! Not sure if it is 365 or exchange 2010 issue

I have a following scenario of nested groups. 

I have a distribution group that within has a few dynamic distribution lists.

When a user (365 user) gets added to the distribution group manually, and that  365user sends an email to that distribution group only he receives an email and no one else (no one from other dynamic distribution lists). However, when someone from on Premise server sends an email everyone is able to receive this email, including 365 user.

please advise,

Marko 

Hi Marko,

We can do the following steps to narrow down the issue:

1. Please confirm if the issue happens when all Exchange Online users who are added to the distribution group send message to this group.

2. Please check whether there is any transport rule configured in Exchange Online or Exchange 2010 to limit this message transport.

3. Please create a new nested distribution group in your environment and check whether the issue can be reproduced.

Regards,