If HDX Adaptive Transport Policy set to Preferred on DDC and when attempting to connect to an Application or Desktop using Citrix Receiver for Windows 4.10 or Citrix Receiver for Mac 12.8 or Citrix Receiver for iOS 7.5 and above, you may encounter below issues:

• Session will get disconnect if initial connection established using TCP protocol
• Session launch may fail by displaying SSL error when you try to Disconnect and Reconnect a session

Citrix has identified this behavior with Receiver for Windows 4.10, Receiver for Mac 12.8, Citrix Receiver for iOS 7.5 and above, and with specific NetScaler firmware versions having HDX Insight or SmartControl functionality enabled. The following table covers the NetScaler builds, which are affected.

Disable SmartControl and HDX Insight on NetScaler.
(or)
Set HDX Adaptive Transport Policy to Off on DDC which will completely disables EDT functionality.
 
To fix this issue, user must upgrade to NetScaler 12.0 release to use EDT functionality.

Problem Cause

For NetScaler 11.1 releases, the HDX Insight/SmartControl functionality embeds certain reconnect data into the reconnect cookie communicated by VDA to receiver for any TCP ICA connection. This reconnect cookie gets invalidated by VDA in scenarios where receiver makes reconnect request with UDP followed by the actual TCP connection due to the fact that NetScaler UDP ICA does not have the support for Insight till date.