The dynamic distribution group is permanently from the One Identity Manager database and Exchange Online system.
To delete a dynamic distribution group
- 
In the Manager, select the Azure Active Directory > Tenants > <Azure Active Directory tenant> > Exchange Online administration > Recipient configuration > Dynamic distribution groups category. 
- 
Select the dynamic distribution list in the result list. 
- 
Click in the result list. 
- Confirm the security prompt with Yes.
