This extension is extremely buggy.
If it gets stuck in a login/error loop, you can open a new tab and log into the captial one website. then re-open this extension and it'll work.
Aside for the login/something went wrong error, it absolutely kills memory usage. Specifically when visiting a site like lowes.com. It maxed out my memory usage and started to freeze firefox. Initially I thought the latest firefox update was the problem. Nope, as soon as I disabled this extension I saw my memory usage drop like a stone.