I don't have this problem when I use git locally on my machine, ONLY when logged in via SSH with PuTTY. FYI my server is using freeSSHd.
Assuming my current directory is my git repository's local directory...
The command git -c diff.mnemonicprefix=false -c core.quotepath=false fetch origin
issues the following error:
FATAL ERROR: Disconnected: No supported authentication methods available (server sent: publickey)
Again, this only happens when I'm logged in via PuTTY and not when I'm in the command prompt when I'm physically at the server.