If I'm in gmail, and use the 9 dot icon, select Calendar, I get a 400 error. If I type calendar.google.com as a URL, it works fine.
If I'm in Google Drive, double-click on a sheet, I get a 401 error (auth). If I open sheets and file File/open to get the same sheet, it opens fine.
If I go to Chrome's 3-dot menu / More Tools / Extensions, and disable Bitdefender Anti-tracker using the slide, then return to those pages, refresh, and try again, those problems go away.
This is Windows 10, Chrome is fully up to date. I purged downloaded pages and cookies, and refreshed pages. Disabling anti-tracker makes the problem go away, links work fine. Re-enabling anti-tracker brings the problems back.
Cheers,
glen