SSH not working from one specific computer

What this means, ultimately, is that the SSH server on the other end has crashed or is in some way not working. It's still listening on the socket but it's not capable of performing a cryptographic handshake.

The only solution is to restart the process on the remote side.

I had this very same problem, what i found was my IP keept getting added to the etc/hosts.deny file.

I resolved this by simply logging into another VPS server then connecting ssh into the blocked VPS and removed my (home static) IP from the hosts.deny file.