Calling POST oauth2/token from browser always results to Forbidden status if you're currently logged-in to your twitter account

[jim]

If I make a request call of POST oauth2/token from browser using REST Client add-on (Rest Easy, DHC, etc) and I’m currently logged-in to my twitter account, the request will always fail with Forbidden (403) status. But if I’m not logged-in to my twitter account and make the request, it will be successful.

Any explanation of this?

Also want to report the [API Console link](https://dev.twitter.com/rest/tools/console) doesn't show the console, the content is just blank:

Tested in many browsers, same result.