Installation of Plesk via Plesk Web Installer fails: Could not connect to the target server. Process exited with status 1

Symptoms

• When installing Plesk via Plesk Web Installer (https://get.plesk.com/) using root or a sudo user as SSH login, initialization fails with one of the following errors:

  Could not connect to the target server. Process exited with status 1

• The migration procedure fails fith the following message:

  Could not connect to the target server. ssh: handshake failed: ssh: unable to authenticate, attempted methods [none password], no supported methods remain

Cause

SSH configuration of the server (source in case of the migration) not allow root login or/and Password authentification:

• The PermitRootLogin or/and PasswordAuthentication are disabled:

  # cat /etc/ssh/sshd_config | egrep 'PasswordAuthentication|PermitRootLogin' | grep -v "#"
  PermitRootLogin no
  PasswordAuthentication no

• The AllowUsers directive is enabled in the SSH configuration file but does not contain the root user:

  # cat /etc/ssh/sshd_config | grep 'AllowUsers'
  AllowUsers johndoe

Resolution

1. Connect to the server (to the source server in case of the migration) via SSH as root.

2. Open the /etc/ssh/sshd_config file in any text editor.

3. Find the PermitRootLogin or/and PasswordAuthentication directives and edit them as follows:

   [BEFORE]
   PermitRootLogin no
   PasswordAuthentication no

   [AFTER]
   PermitRootLogin yes
   PasswordAuthentication yes

4. If the AllowUsers directive is present in the SSH configuration file:

   # cat /etc/ssh/sshd_config | grep 'AllowUsers'
   AllowUsers johndoe

   add the root user as well to the AllowUsers directive:

   [BEFORE]
   AllowUsers johndoe

   [AFTER]
   AllowUsers johndoe root

5. Restart the SSH service to apply made changes:

   # service sshd restart

6. Restart Plesk installation via Plesk Web Installer/Proceed with migration.