I\'m installing ruby in windows 8.1 pro
ruby 2.1.3p242 (2014-09-19 revision 47630) [x64-mingw32]
and gem version
2.2.2
Try to uninstall ruby and re-install a previous version. that worked for me once.
another solution is to type this in cmd: set = HTTP_proxy http://10.1.143.126:3128
and try again
This command will fix it -- you need to change the code page of the current terminal.
chcp 1252