If Firefox has the following settings, you will get an "An unknown error occurred" error when you try to log in to Lastpass.
History Firefox will Never Remember history

If Firefox has the following settings, you can log in without any error.
History Firefox will Remember history

Firefox 81.0
Lastpass 4.56.1.3

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I can now log in after updating to Lastpass version 4.57.2.5 (September 28, 2020).

No longer works with Firefox. They might want to outsource their QA before releasing updates.

Log in in browser always states unexplained error.

Small Frustrations
The extension is great and I can understand the reason for some of the things which cause frustration. But it would be nice if you could designate a "home" computer which would stay logged in at all times. It may be only once every 30 days but each time I consider uninstalling the extension.

Last version doesn't work

Now a total liability. Update your browser - loses everything for who knows how long. No tech help, no solutions, nothing - just left totally high and dry without warning. No longer usable, essential to avoid.

Everytime firefox updates, Lastpass stops working for several days. TERRIBLE!!!!

Only lets me log in if I go to "manage one time passwords" on their website. Needs to be fixed, would be 4 star if this massive bug is sorted.

I am unable to log into my LastPass account in the Firefox browser, while I can in other browsers.

Unable to log in on Firefox

After the last update I can't login with this add-on. The error message is: An unknown error occurred.Dismiss.

I use Firefox 80.0.1.
Lastpass version: 4.56.1.3
Mac OS: 10.15.6 (19G2021)

I have loved it and recommended it, and after a brief hiccup, I love it again.

All I have ever ready about LastPass has been great. However, attempting to get it to work has been nothing but a headache.

Until last update 4/5 stars, after september update not work login to my account on FF 80.0.1-81.0 (64 bit) my main browser. Unable to use.

Piece of crap. I've been using this because I have a client that's a huge fan but in the past two years, it's been nothing but a giant headache for me. Autofilling the wrong passwords, duplicating many of the logins even when I don't save them and just in general sucking. Works passable on Chrome but the Firefox add on is pure junk.