SSH is failing connections

Not certain whats happened here, but any SSH connection to my server is failing. Yesterday it working, today it is not. I am on a Windows machine using Putty. I can connect to the IP on port 22. If I type the wrong password, it gives me the password prompt again. If I provide the correct password it either just closes the session window or gives me an error "Server unexpectedly closed network connection". On my local FW the logs are showing the session ended due to a tcp-fin packet - meaning the remote server closed the session. From within cPanel I use the Terminal app to emulate a console session and I am able to get root command line: [root@sX-X-X-X ~]#. From there I then ssh to itself: ssh ='username@x.x.x.x'>username@x.x.x.x - and I get this error: dup() in/out/err failed I restarted the sshd and the problem persists. What can I do or look at to get this resolved?