How can I log in to my Thunderbird account when my password doesn’t work?

I’m having trouble logging in to my Thunderbird account on my laptop. My password doesn’t work, and when I click “Log in,” I’m redirected to a website, but I still can’t access my account. It also seems like Thunderbird doesn’t recognize or find my account at all. Instead of allowing me to log in, I’m being told to join some kind of waitlist, which doesn’t make sense because I already have an account and need to access it. I urgently need to use my account for work, so I would really appreciate any help with recovering access and getting Thunderbird to recognize my existing account.