While looking to my /var/log/message on Linux ( Squid Server, DHCP), i saw the error message shown as title of the post, so after a bit googling i find the solution that it is due to the direct login failure to the proxy server, so to turn off these messages and to avoid the problem we have to disable the direct login of the root account.
The sshd_config file is located at /etc/ssh/sshd_config and it is probably the most common place to find it. If not, we can search for it
# edit sshd_config file
What we want to do is edit this file. We need to uncomment and edit just one line inside this file, at least.
# Vi /etc/ssh/sshd_config
we should be viewing the contents of this file now. We're looking for
Just remove the hash sign (to uncomment the line, or enable it) and change the value to NO. It should look like this after the modifications:
To make the changes working we have to start the sshd services
# service sshd restart
Now everytime we try to login to our proxy we will using our ordinary user account and then we can substitute to root user.
I hope this will be informative for you !