I have to use college proxy server to access the college network. After setting system proxy settings, we have to login at an online college proxy portal before being able to use their internet. Most of the times, the login portal is accessible via HTTP protocol, and when logging in, the form submits a POST request to their server and gets redirected to a "login_success" page, always via HTTP protocol. But every once in a while, when accessing the login portal through HTTP protocol, it redirects to the same URL but using HTTPS protocol, and when you try to login, the POST request fails with NS_BINDING_REDIRECT error, probably because it gets redirected to "login_sucess" page with HTTP protocol. No such error is raised on chromium, and I am able to login without any problem there. Any help would be much appreciated.

TLDR: NS_BINDING_REDIRECT error when logging at an online portal, since the login page uses HTTPS protocol, and successful login attempt via POST redirects to a success page using HTTP protocol.