The subject says it. No method of https cloning that I've tried works. I can log into my Atlassian account and see the (private) repository I need to participate in. I've tried command line and Tortoise git. I use the same user name that my profile information reflects, and the same (updated) password that I use to log into the website (after closing all browser instances and clearing my cache).
I'm running Windows 10 and Firefox.