How to change account with app sign in?



I have a twitter app and have implemented signin from a website (wordpress plugin) as per it works fine, until I want to change the twitter account.

I restart the above process, and the twitter login screen comes up, I enter the second user credentials, but when it returns to my website, it is still using the first user. (I set force_login=true for oauth/authenticate).

Any idea what I am doing wrong?