1Password 6 used to work in Firefox until a few weeks ago

Hello Arthaey​! 👋

Welcome to the community! So that folks don't have to navigate over to the other post, I'll post a similar reply here. Both 1Password 6 and the 1Password classic extension haven't been updated in many years (since 2018 for 1Password 6 and 2019 for the classic extension) and they're no longer supported, you can find more details here: The 1Password classic extension may no longer work in your browser

To continue using 1Password in your browser, I recommend that you upgrade to 1Password 8 which has been developed and tested for the latest versions of Firefox and modern operating systems: Upgrade to 1Password 8

Having my password manager in the cloud, behind a subscription, which I could lose access to if the company ever went out of business or if they just decided to suspend my account for who knows what reason…

With a 1Password account, if you ever decide to stop your 1Password subscription, your account will go into a read-only state and you'll still be able to view and export your passwords: If your 1Password account is frozen

If you're using the 1Password 8 app on your devices, then your passwords are cached locally on your device and would be still available to you even if our servers disappeared tomorrow. 

That said, thank you for being part of 1Password for so many years. If you decide to move on, I truly hope you find a solution that fits your needs.

-Dave