I was using Git with beanstalk in windows 7. Now I got new system with Windows 8.1. Now I configured Git and Tortoisegit with new system.Its working fine in local commit but
I opened TortoiseGit->Settings -> Network and in SSH Client I changed "ssh.exe" instead of "TortoiseGitPlink.exe". Now it works fine.
TortoiseGit may, from time to time, unload your putty key.
Simply open TortoiseGit -> Settings -> Git -> Remote
Then reload your putty key for your chosen remote connection (e.g. origin)
I received this error because my key agent (KeePass KeyAgent plugin) didn't have the correct key loaded anymore. Added the correct key and everything was fine.