Hi everyone, I have updated this post and the linked extension VSIX to reflect changes I have made. Please try this again using the new version and let me know your feedback!
Studio is still available from the WRC as an independent download. See this DC post for more details. I am happy to help you get VS Code working, but to know what is wrong I will need to see your code-workpsace file, server connection info and possibly a network trace since VS Code talks to IRIS via HTTP(S). If you're more comfortable doing that in private you can open a WRC case and they will help you. You can link this post there so they have more context. This feature has existed in VS Code for 4.5+ years so I think there's some sort of configuration issue and not a product defect. Also, any feedback on how we can make VS Code better can be communicated to WRC, your account team, or by posting an issue on GitHub.
@Pietro Di Leo
That error has nothing to do with compilation. It didn't even get that far. VS Code tried to save that file on the server, but it failed. There should be an error in the ObjectScript Output channel. If not, a network trace will show us the HTTP error response.