If you get the error "The workbench failed to connect to the server (Error: Connection error: Unauthorized client refused: auth mismatch)" when trying to connect from one VS Code instance to VS Code tunnel on another machine do the following workaround:
- Open the remote URL in the browser.
- Close the tab few times before "Yes I Trust" popup appears, press it.
- Done. Now you can again use the desktop version to connect to a tunnel.
Thanks Microsoft...