Every piece of software is not perfect. We have plenty of bugs. Some of them are minor and do not do many harm but sometimes there are those nasty ones which are harder to detect. When you deal with them you may even not see them on the first glance even if you are looking just at them.
At the first glance it could be hard to spot error here.
jQuery does have nice function for getting JSON data from server by GET request : jquery.getJSON. But there is no function to make request for JSON data by POST request. If you would like to have analogic functionality like getJSON but with POST requests then you can download my npm package post-json-for-jquery .
From time to time TFS asks me about password. And sometimes there is a moment that after I input correct credentials then TFS displays again login form and without thinking I am trying to input another password. And what is TFS doing then? Silently accepts wrong password and it is going to keep silent until i want to do check in or something connect to source control. But after I want to do something with TFS then… TFS30063 error appears. I think that I found a way to deal with it.