I can see an error at https at the first screen shot which means certificates weren't properly configured.
and pls give me the exact log that you see in the desktop logs.
have you configured any proxy server ?
Your SSL Certs are not added to host file or there are some issues with it.
You need to open your window's host file in notepad as admin located @c:\Windows\System32\drivers\etc and match IP with the name.
This will work.
Thank you for your help Krunal.
Sorry for the late update.
We have fixed it by adding https between proxy and tableau server.
Thanks for the reply back. That's what my question before to you
You may close the question now
Oh sorry Lakshmi, i missed your reply. I will mark your answer as correct answer thanks a lot!