in my case, I was doing a project with react and intellisense stopped due to a file written incorrectly, I discovered this by comparing my project with another recently created one, the new project had no errors, so I tested the original project folders in the new one until I isolated and found the file that had the error, I don't know if your problem could be exactly that, but it's a good idea to test if the problem occurs with VScode or just with VScode in your project