Fix "ERROR: Cookies are blocked or not supported by your browser"

Hello, I just upgraded to WordPress 4.1.1 on all my sites and I’m having extreme trouble logging in. I keep getting this error: “ERROR: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.”

I’ve tried the following all to no avail:
1. Clear cache and cookies on browser
2. Use different browsers on different computers and even different OSes
3. Renamed themes folder (got a white screen)
4. Renamed plugins folder (no effect)
5. Edited wp-config and wp-login.
6. Replaced wp-config and wp-login files from fresh WordPress 4.1.1 install.

This seems to be an issue with 4.1.1
I am at my wits end and would appreciate any suggestions.

Thanks,
N. Somto