I cannot get to login.yahoo.com on my Win 10 1809 computer (or earlier
versions of W10). This is true on IE, Edge, Firefox, Opera, and even
lynx. If I plug my XP computer into my internet connection at home, it
works fine getting to the login page.

I have to use a proxy to get to and past the login page in Win 10. Once
logged in, and at mail.yahoo.com, I can turn off the proxy and it works
fine. I can get to sports.yahoo.com, search.yahoo.com, and other
*.yahoo.com pages without a proxy.

The hosts file, with no *.yahoo.com addresses in it, or giving an IP
number that nslookup returns for login.yahoo.com, does nothing.

Changing resolv.conf does nothing. Changing to use DNS over HTTPS in
Firefox does nothing. Going to Network Connections - right click -
Internet Protocol Version 4 (TCP/IPv4) properties and changing from
obtain DNS address automatically to typing in IP numbers of various
DNS servers does nothing.

I can go to another home/apartment and use their Wi-Fi, and my computer
doesn't work there either. If I use my computer as a Wi-Fi hot spot,
and connect my phone to the computer, I can use yahoo's email app
without any problems.

Any ideas? This has been driving me crazy for over a year with no
resolution. TIA.