After rebooting my up-to-date MacOS workstation via Safari, I entered the long address: https://www.cloudflare.com and landed on Cloudflare (out for maintenance) website with links to status (apparently Seoul Cloudflare is out of service).
I retried FireFox and I was able to login normally.
I feel this is a hint that my safari sessions are being redirected.
Why? How? Does my Mac have a virus?