You need to remove your PTA agent to stop the sync. If the PTA agent is running then PTA will remain active and continually handles user sign-in requests. You can go to Control Panel -> Programs -> Programs and Features and uninstall both the Microsoft Azure AD Connect Authentication Agent and the Microsoft Azure AD Connect Agent Updater programs. Once done you can check AAD Admin portal if the agent is "In-Active". If so, it will be automatically removed after few days from the portal.
Cannot turn-off pass-through authentication
MGCH
41
Reputation points
I wanted to test the pass-through authentication and enabled it for my Azure tenant.
All good and the test was successful, but now I cannot remove it.
I disabled it in ADconnect, but it is still showed as enabled in Azure. I'm OK with that, because it is a testing tenant, but I'm receiving unsuccessful synchronization emails every day and it is a bit annoying.
Am I missing something? What is the way to disable it completely?