I use several OS's: Os/2Warp, eComStation, Windows 7, and Ubutu.
Mozilla Thunderbird or SeaMonkey are my favorite email clients
My Hotmail has been a challenge this past several days. I found a solution .. at least on a W7 machine (Ubuntu, OS/2 and other W7) machines would work, was to make sure the TLS 1.0 was enabled.
I wonder if some 'upgrades' turn this off going to a higher level for security or not. Anyway this worked for me here on this combination of software.