You may have had a security scan of your web server, and found the results of a weak algorithm with your SSH "Cipher Block Chain" Mode Ciphers - See Wikipedia for details.
The default /etc/ssh/sshd_config file may contain lines similar to the ones below:
To disable CBC mode ciphers and weak MAC algorithms, add the following lines into the: nano /etc/ssh/sshd_config
Restart after you have made these changes. SSH -Q cipher sudo systemctl status sshd ls -la ~/.ssh |