Today I logged into the web console on Exchange 2013 and wanted to added a few new users to the main DL. Everything went in fine however when I clicked save the following error was returned.

“You don’t have sufficient permissions. This operation can only be performed by a manager of the group”

So in AD I was the owner, had all the permissions and still Exchange didn’t want to budge. I then ran the following command from Powershell for Exchange:

Set-DistributionGroup -Identity <Name of DL> -BypassSecurityGroupManagerCheck –ManagedBy <username>

After this my name appeared as the Owner on this DL which it didn’t before and I was able to add in all the new users.

Hope it helps.