If the logon client cannot connect to the logon agent, particularly in the scenario of offsite logon, then use the tool "clo-handshake" to test if the cause of the problem lies in the network configuration or in the application configuration.
Click here to download the CLO Handshake Tool
You can leave the file in Downloads or move ita different directory. Just make a note of which directory it was moved to.
Open a Command Prompt and CD to the directory into which the CLO Handshake Executable has been placed.
Type the following.
clo-handshake-x.x.x dsagent.yourdomain.com 12841