Unable to start SSH session or Plesk migration: Failed getting banner

Symptoms

• Plesk migration fails:

  Error: launchpad error (Error code = 2):
  == STDERR ====================
  Unable to start SSH session: Failed getting banner
  ==============================

  OR

  Plesk for Linux is not found on the specified source server.

• Cannot connect to the source server via SSH:

  # ssh 203.0.113.2
  ssh_exchange_identification: Connection closed by remote host

Cause

Not enough connections permitted for SSH service on the source server.

Resolution

Note: if you don't have root access to Plesk via SSH, contact your hosting provider regarding the issue

1. Login to the source server over SSH. If it is not possible, log in via local server console.

2. Uncomment MaxStartups parameter in/etc/ssh/sshd_config and set the following value:

   MaxStartups 50

3. Reload SSH server configuration to apply the changes:

   # service sshd reload