Exchange 2010 ActiveSync error with the latest Exchange iApp template

I configure BIG-IP LTM with the Exchange iApp template f5.microsoft_exchange_2010_2013_cas.v1.2.0. When I tested the ActiveSync connectivity with testexchangeconnectivity.com, I got the following error in the FolderSync test:

 

Attempting the FolderSync command on the Exchange ActiveSync session. The test of the FolderSync command failed.

 

Additional Details Exception details: Message: The request was aborted: The request was canceled. Type: System.Net.WebException Stack trace: at System.Net.HttpWebRequest.GetResponse() at Microsoft.Exchange.Tools.ExRca.Extensions.RcaHttpRequest.GetResponse()

 

If I bypass BIG-IP and test the server directly the problem doesn't exist.

 

All other tests through BIG-IP are fine, except this ActiveSync test My BIG-IP version is 11.3 HF6.

 

Is there anything wrong?