Over the last several months I've started having a lot of issues with firefox. I've been unable to watch videos on certain sites, ones for livestreaming especially, and unable to login on others. Its like the buttons are disconnected or something. I'll press the login button and nothing will happen.
I've had to use chrome, though I've recently decided to use edge instead, for livestreaming sports, logging into crunchyroll, and reddit, among others.
I'm still getting greyed out login buttons on certain sites.
So its likely not your ISP or other site issues. Looks like in another comment you said it could be an add-on. Like debugging skyrim disable all addons and enable then one at a time till you find the problem. If you do find the problem you might want to check the addons git and report a bug if not already found.
I tried that disabling addons helps with certain sites but not others. I can't find a clean fix.
Maybe try an uninstall and reinstall.
Before you uninstall in Settings -> Privacy & Security -> Cookies and Site Data, clear all site data and cookies.
That's all I got. Best of luck!
thank you sweetie