If you're seeing a "Temporary Error (502)" message or other server error message when you try to access Google Docs, Sheets, or Slides, it means that your documents are temporarily unavailable. These errors generally resolve themselves within a few minutes, so please wait a bit before trying to access them again.
If Google Drive loads but your items aren't displayed, trying clicking on any other view, such as "All items" or "Owned by me." This should make the error message disappear and your files appear as normal.