It is not possible to access SSH terminal extension via root user in Plesk: ssh_exchange_identification: read: Connection reset by peer

Symptoms

Plesk Admin cannot access SSH through the SSH terminal extension via root user:

Connection Broken 

Cause

Root login to SSH is disabled on the system level. 

Resolution

1. Connect to the server via SSH
2. Open /etc/ssh/sshd_config in any text editor and add the following  lines:

   Match Address 127.0.0.1
   PermitRootLogin yes

3. Restart SSH service:

   # service sshd restart