URL: https://www.hbogo.com.br/authentication/login/frame
Browser / Version: Firefox 75.0
Operating System: Windows 10
Tested Another Browser: Yes
Problem type: Site is not usable
Description: Can´t Login with my ISP TV credencials
Steps to Reproduce:
Since Saturday, I´ve tested on others browser (various sites that uses my ISP TV credencials) and all is good, but on FF Nightly all sites is not login. Already spoken with HBO, nothing wrong with Account, just spoken with my ISP and no problem as also. Since tested on Microsoft Edge and Canary and it worked, the problem is really only by FF Nightly side.
View the screenshot

Browser Configuration
From webcompat.com with ❤️
URL: https://www.hbogo.com.br/authentication/login/frame
Browser / Version: Firefox 75.0
Operating System: Windows 10
Tested Another Browser: Yes
Problem type: Site is not usable
Description: Can´t Login with my ISP TV credencials
Steps to Reproduce:
Since Saturday, I´ve tested on others browser (various sites that uses my ISP TV credencials) and all is good, but on FF Nightly all sites is not login. Already spoken with HBO, nothing wrong with Account, just spoken with my ISP and no problem as also. Since tested on Microsoft Edge and Canary and it worked, the problem is really only by FF Nightly side.
View the screenshot
Browser Configuration
From webcompat.com with ❤️