I think this may be caused by addons you have installed in Firefox. And US Bank has made some changes on their side to be more sensitive to some things addons block or change. So here are a few example addons that break random sites & cause weird issues with logging into sites: * ClearURLs * Ghostery (once broke logging into Barclays bank site) * Disconnect If you have any of these 3, disable them & restart Firefox. In one case, Disconnect was breaking a payment site called Stripe.com. It was not enough to disable this addon. It had to be completely uninstalled to get rid of the payment not going thru issue on Stripe.com. If disabling any of those 3 addons don't fix the issue on US Bank, please try disabling more of your addons or all of them at once, then return to Firefox and test your bank site again. You may need to restart Firefox after disabling the addons & you probably should clear your cache & cookies as well.