If TSWeb Client is installed on the terminal server:
Locate connect.asp on the server. For example, go to c:\inetpub\wwwroot\tsweb.
Using Notepad, open connect.asp.
Add the following line before MsTsc.Connect():
MsTsc.AdvancedSettings. PluginDlls="tsslsso.dll"
The vcd\rdp directory has an example connect.asp file that you can refer to.
Save and close the file.