System users are not able to connect to a Plesk server over SSH/SFTP: No supported authentication methods available

Symptoms

• Access to a Plesk server over SSH/SFTP under a subscription's system user fails with one of the following error messages:

  Permission denied (publickey).

  ---

  Disconnected: No supported authentication methods available (server sent: publickey,gssapi-keyex,gssapi-with-mic)

  ---

  can't connect to remote host: authentication failed

• Access to the server over SSH is allowed at Domains > example.com > Web Hosting Access.

Cause

Password authentication for SSH connections is not enabled on the server:

# grep PasswordAuthentication /etc/ssh/sshd_config
PasswordAuthentication no

Resolution

Note: This solution is intended for Plesk administrators only. If you are a domain owner, please contact your service provider for assistance.

1. Connect to the Plesk server via SSH.

2. Create a backup of the /etc/ssh/sshd_config file:

   # cp /etc/ssh/sshd_config /etc/ssh/sshd_config.back

3. Open the /etc/ssh/sshd_config file in a text editor. In this example, we are using the vi editor:

   # vi /etc/ssh/sshd_config

4. Enable password authentication for SSH connections:

   PasswordAuthentication yes

5. Save the changes sand close the file.

6. Restart the SSH service:

   # service sshd restart