Ever since IE has disappeared, I was really hoping that Firefox would cover that gap. But no, now it's Chrome.
My banking login fails on Firefox unless I close and re-open. I have several companies, and if I log out of one company, and then try to switch to a different one, the login fails. Every **bleep** time. Bank is Royal Bank of Canada.
Went to ticketmaster through my CFL team's website, and Firefox wouldn't let me login at all. Just a straight fail.
For both of these, when I switched to Chrome, it all worked flawlessly. I really don't want to use Chrome, but am getting to the point where I can't seem to get around it.
Many sites use multiple servers, and Firefox's Total Cookie Protection feature can prevent successful login in that situation. You can test disabling Enhanced Tracking Protection on those sites. See: https://support.mozilla.org/kb/total-cookie-protection-and-website-breakage-faq