On computer with AD Sync program I see next error in the Event Log:
Source: Directory Synchronization
ID: 662
Password hash synchronization health task failed during ping operation. Details:
System.InvalidOperationException: An error occurred, SynchronizationEngineManagedHandle.cpp(190), code 80004005,
BAIL: MMS(4376): ..\PasswordHashSync.cpp(748): 0x80004005 (Inidentified error)
Azure AD Sync 1.1.880.0
в SynchronizationEnginePasswordHashSyncManagedHandle.Ping(String state)
в Microsoft.Online.PasswordSynchronization.Fim.FimNotificationManager.Ping(String forestInfo, TimeSpan interval)
в Microsoft.Online.PasswordSynchronization.RetryUtility.ExecuteWithRetry[T](Func`1 operation, Func`1 shouldAbort, RetryPolicyHandler retryPolicy)
в Microsoft.Online.PasswordSynchronization.HealthTask.SynchronizeCredentialsToCloud()
<forest-info>
<forest-name>sfh.local</forest-name>
<connector-id>7c571cb9-7abd-44c1-9d67-6f2e7668990b</connector-id>
</forest-info>
What's is the problem?