The connected user is not an Analysis Services server administrator. Only an administrator can make changes to server properties

You are a part of the local administrators group on the server. You want to add a user to the Server administrator group of your Analysis Server. After adding the user you will get next error message: The connected user is not an Analysis Services server administrator.  Only an administrator can make changes to server properties.

Solution: Start SQL Server Management Studio with the option 'Run as Administrator'. Now it is possible to add users to the Server administrator group of your Analysis Server.