ActiveSync exception on Exchange 2016

Question

I get this error on my event after restart IIS.
I run this two command for resolve error but error is exist.
Get-Mailbox | Set-CasMailbox -ActiveSyncEnabled $False
`Get-Mailbox | Set-CasMailbox -ActiveSyncEnabled $True'
Error:

Level Date and Time Source Event ID Task Category
Warning 1/3/2023 11:37:52 AM ASP.NET 4.0.30319.0 1309 Web Event "Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 1/3/2023 11:37:52 AM
Event time (UTC): 1/3/2023 8:07:52 AM
Event ID: 7c89094cd79849efb70201ca892246f8
Event sequence: 3
Event occurrence: 1
Event detail code: 0

Application information:
Application domain: /LM/W3SVC/2/ROOT/Microsoft-Server-ActiveSync-1-133171417813586892
Trust level: Full
Application Virtual Path: /Microsoft-Server-ActiveSync
Application Path: C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\sync\
Machine name: EX-MB-03

Process information:
Process ID: 17228
Process name: w3wp.exe
Account name: NT AUTHORITY\SYSTEM

Exception information:
Exception type: ThreadStateException
Exception message: Thread has not been started.
at System.Threading.Thread.JoinInternal(Int32 millisecondsTimeout)
at System.Threading.Thread.Join(TimeSpan timeout)
at Microsoft.Exchange.AirSync.Common.NotificationManager.ShutdownNotificationManagerTimerThread()
at Microsoft.Exchange.AirSyncHandler.Global.ExecuteApplicationEnd(Object sender, EventArgs e)

Request information:
Request URL:
Request path:
User host address:
User:
Is authenticated: False
Authentication Type:
Thread account name: NT AUTHORITY\SYSTEM

Thread information:
Thread ID: 114
Thread account name: NT AUTHORITY\SYSTEM
Is impersonating: False
Stack trace: at System.Threading.Thread.JoinInternal(Int32 millisecondsTimeout)
at System.Threading.Thread.Join(TimeSpan timeout)
at Microsoft.Exchange.AirSync.Common.NotificationManager.ShutdownNotificationManagerTimerThread()
at Microsoft.Exchange.AirSyncHandler.Global.ExecuteApplicationEnd(Object sender, EventArgs e)

Answer 1

Hi @Ehsan Rabiee ,

Is it causing any activesync issues in your organization?
Aside from restarting IIS, did you make other changes in your environment?

Please try recycling the MSExchangeSyncAppPool via IIS manager and see if it can help.

In case the warning persists, I'd suggest restarting the Exchange server out-of-hours to check the result.

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