Re: External recipients in distribution groups

Hi Jens,

Based on my testing, the issue occurs if the DG owner isn't an administrator of the Exchange Online.

In this situation, I suggest you add the administrator to the Ownership of the DG.

After that, login to Office 365 Admin Portal with the administrator user>click Settings under Outlook>click Distribution Groups under Users & Group>select the DG and click details.

Thanks,

Keats Ge