https://www.XXXXXXXXXXXXXX.com/umbraco/backoffice/UmbracoApi/Authentication/PostLogin
Failed to load resource: the server responded with a status of 400 (Bad Request)
This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/104268-failed-to-load-resource-the-server-responded-with-a-status-of-400-bad-request-while-login-umbarco-backoffice