The MSExchangeSyncAppPool application pool crashes on a server that hosts an Exchange Server 2007 Client Access Server role

Event Type: Warning
Event Source: W3SVC
Event Category: None
Event ID: 1011
Description:
A process serving application pool 'MSExchangeSyncAppPool' suffered a fatal communication error with the World Wide Web publishing Service. The process id was '<process id>'. The data field contains the error number.

Event Type: Warning
Event Source: W3SVC
Event Category: None
Event ID: 1009
Description:
A process serving application pool 'MSExchangeSyncAppPool' terminated unexpectedly. The process id was '1948'. The process exit code was '0x1'.

Event Type: Error
Event Source: W3SVC
Event Category: None
Event ID: 1002
Description:
Application pool 'MSExchangeSyncAppPool' is being automatically disabled due to a series of failures in the process(es) serving that application pool.

1. Open the Internet Information Services (IIS) Manager console.
2. In the console tree, expand Internet Information Services, expand the node that corresponds to the server name, and then click Application Pools.
3. In the details pane, right-click MSExchangeSyncAppPool, and then click Properties.
4. On the Health tab, check the settings under the Enable rapid-fail protection section.

Exception type: System.IO.IOException
Exception message: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
Exception level: 0
Exception stack trace: at System.Net.ConnectStream.EndRead(IAsyncResult asyncResult)
at Microsoft.Exchange.AirSync.ProxyHandler.BackEndReadContent(IAsyncResult asynchronousResult)
Inner exception follows...
Exception type: System.Net.Sockets.SocketException
Exception message: An existing connection was forcibly closed by the remote host
Exception level: 1
Exception stack trace: at System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)
at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)