Unable to upgrade distribution lists to Office 365 groups

Applies to: MSfC O365-Exchange OnlineExchange Online

Symptoms


You can't upgrade your distribution lists (which are also known as distribution groups) to Office 365 groups. 

Cause


This issue occurs if a custom email address policy is applied to the tenant for the Office 365 groups. 

Resolution


To resolve this issue, you have to remove the email address policy for the distribution groups. Then, try again to upgrade the distribution lists to Office 365 groups. For more information about how to remove the email address policy, see Remove an email address policy

For more information about how to upgrade distribution lists, see Upgrade distribution lists to Office 365 Groups in Outlook