KB ID 0001649
Problem
I’m doing some work for a client that has Azure AD Sync running, and we keep kicking each other off the server, so I thought I’d login with another account. However, when I tried to open the Synchronisation Service Manager;
Unable to connect to the Synchronisation Service
Some possible reasons are:
1) The service is not started.
2) Your account is not a member of the requires security group.See the Synchronisation Service documentation for details.
Solution
Well it was the second option in my case. Open Server Manager > Tools > Computer Management > System tools > Local Users and groups > Groups > ADSyncAdmins > Add your user in here.
Related Articles, References, Credits, or External Links
NA