When this happens, do the following in Azure AD Connect:
- In “Customize synchronization options”, disable (uncheck) the password hash sync option.
- Wait for sync to complete, watching in the Operations tab of the Synchronization Service Manager.
- In “Customize synchronization options”, enable (check) the password hash sync option.
- Wait for sync to complete, watching in the Operations tab of the Synchronization Service Manager.
- Check the Office 365 admin readout.