@Glenn Maxwell Thank you for following up on this!
When it comes to assigning the Owner built-in RBAC role to an Azure Subscription, if your DL was created solely from the Exchange Admin Center, you'll have to first find out what type of Group it is - Security or Microsoft 365. For more info - Group Types.
- Navigate to Azure Active Directory
- Select Groups from the left pane
- Search for your Distribution list

Once you find out your Exchange Online DL's type, if your DL's Azure AD Group is of type Microsoft 365 or Distribution, you won't be able to assign an RBAC role to these group(s). However, you can resolve this by either creating an Azure AD Security Group from the same page and assigning your DL members to this group, or you can assign your DL members the Owner RBAC role individually.
Creating an Azure AD Security Group:
If you intend on creating a new Azure AD Security group and assigning all your DL members to this group.
- Within Azure Active Directory
- Select Groups from the left pane
- Select New Group
- Select Group Type - Security
- Fill in the required fields and add your Exchange online DL users to the group
- Create your Azure AD Security group.

Once you've decided if you want to create a new Azure AD Security group or individually assign RBAC roles, you can follow the below steps to assign the Owner role to your DL members.
Assign the Owner RBAC Role:
- Within the Azure Portal
- Navigate to Subscriptions
- Select your Azure Subscription
- Click Access Control (IAM)
- Click the Role assignments tab to view the role assignments at this scope
- Click Add > Add role assignment
- Select the Owner role and your
Azure AD Security Grouporselect the specific users. - Once you've made the correct selections Review + assign.

I hope this helps!
If you have any other questions, please let me know. Thank you for your time and patience throughout this issue.
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