This might be understandable if they have various sets of blocked/disallowed content depending on local laws, but OTOH I wish they'd more clearly communicate why you're being blocked then.
I've also had trouble logging into Twitch a few times over the last year on Firefox, but the same is true for Paypal. Both of them don't work in a private window without any addons either, and at least for Paypal changing the user agent didn't help. Twitch works fine If I'm already logged into Twitch, same with Paypal. Just the login fails for some reason.
There's other payment options, and I seldomly watch streams anyway.
Usually it means that OP either uses a "hardened" fork, or did some messing around with about:config like resistFingerprinting, without understanding the ramnifications of such hardening on various web technologies that aren't primarily related to tracking/tracing.
It was doing this to me a while back. Are you using a VPN or using an ad-blocker specifically for Twitch's embedded stream ads? (e.g. TTV-LOL-Pro) The latter work by using proxies and so I think trigger the same sort of effects. Disabled it and it worked fine. It also happened on a Chromium-based browser when I tested it out.
Yup, most of my passwords are like 30 characters, and I don't remember any of them except the one to unlock my password manager (and a couple other important ones).
Just a comment: IMO it's not worth using strong passwords on which you depend on privative/unknown security platforms. Who knows how many times they get hacked or have backdoors? Unless they specify they only store the hash I refuse to sacrifice one of my strong passwords.
Edit: To all talking about password managers. I don't believe in single point of failure as a way to go. The fact that i've to explain that xd...
Genuinely terrible advice. Every popularly available password manager service hashes all your passwords, if they have a data breach they have extremely strict reporting compliance and the majority of services will re-hash all your passwords. If youre so extremely concerned about that, host your own.
But what concerns me the most is
Unless they specify they only store the hash I refuse to sacrifice one of my strong passwords.
Keeping all on one password (password manager) is a single point of failure, which i don't like. I mean sacrifice because my brain can only remeber a few 512bytes long passwords (again i don't use password managers because of single point of failure).