You must have the following ports open for outbound communication: 10022/TCP, 10225/TCP, and 3391/UDP.  You may use the links below to quickly test if your network allows you to use these ports by clicking each of the links below:

KB180601 - Error when connecting.

You receive the following error when trying to connect to a RemoteApp or Desktop Connection:  

Your computer was unable to connect to the remote computer. Try to reconnect. If the problem continues, contact the owner of the remote computer or your network administrator.

You will also notice the following Warning in the Event Log under Applications and Service Logs\Microsoft\Windows\RemoteApp and Desktop Connections\Operational:

Remote application (xxx) is launched on RemoteApp and Desktop connection ( but no stored credentials are used for single sign on. (Reason - RemoteApp and Desktop connection does not exist)

To resolve this issue, follow these steps:

  1. Verify wksprt.exe process is NOT running.
  2. Open Command Prompt as administrator, and run this command:
    regsvr32 wksprtps.dll
  3. You may also need to remove and re-add the RemoteApp and Desktop Connections entry in Control Panel (refer to Setup Guide).