Hi @codewarrior ,
I am not familiar with these extensions, but I just did a search in my Cursor extensions sidebar and could see a C/C++ for Visual Studio Code extension by ms-vscode, is that what you are looking for?
You could perhaps open up dev tools via:
Cursor > Help > Toggle Developer Tools
and then switch to the Console tab and see if you get any errors when you try and search for things in the marketplace.
I know that one other user had some issues with getting themes from the marketplace, so perhaps it is a similar issue?
Perhaps also share system information from:
Cursor > Help > About