Recommended solution for AJAX, CORS, Chrome & HTTP error codes (401,403,404,500)
Just ran into this issue. Setting the HTTP headers for the 401 response did the trick for me. The library I was using wasn't doing this properly without some customization. e.g.:
self.headers["Access-Control-Max-Age"] = '1728000'
self.headers["Access-Control-Allow-Origin"] = "http://localhost:3001"
self.headers["Access-Control-Allow-Methods"] = "ANY"
self.headers["Access-Control-Allow-Credentials"] = 'true'