We are using VS Live Share inside Visual Studio Code and the person who joined cannot open a shared HTML file with the Live Server extension. It says: "Cannot GET .../index.html". Does Live Server only work with "local files"? There is also no option to open the shared HTML file in the file system and to open it that way.
From the changelog of the Live Server extension:
Version Date Changelog 5.2.0 16.11.2018 — [Features] Live Server + Live Share = 💘. Share your live server over the internet with live reload feature! You'll be prompted to share live server using live server when you click to Go Live. (Thank you so much Alex Panov for opening PR #232 )
— [Docs fixing / update] #170, #185, #201, #233 (Thanks Shaurya Shubham, Benjamin Vincent, Jan Dittrich, Karsten 7.)
See also https://github.com/ritwickdey/vscode-live-server/blob/master/src/LiveShareHelper.ts.