Migration from cPanel to Plesk failed: Incompatible ssh peer

Symptoms

The following error occurs on attempt to start a migration from cPanel to Plesk:

PLESK_ERROR: Failed to perform action: Fetch data from source cPanel
Cause: Failed to connect to the the source server 'cpanel' (203.0.113.2) at '203.0.113.2' by SSH as 'example.com': Incompatible ssh peer (no acceptable kex algorithm)
That is a critical error, migration was stopped.

Cause

SSH ciphers are misconfigured on the source server.

Resolution

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

   CONFIG_TEXT: Ciphers [email protected],[email protected],aes256-ctr,aes128-ctr
   MACs [email protected],[email protected],[email protected],hmac-sha2-512,hmac-sha2-256,hmac-ripemd160,hmac-sha1
   KexAlgorithms diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1
   
   

3. Reload sshd service:

   # service sshd reload

4. Start the migration again.