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Article ID: 121904, created on Jun 4, 2014, last review on Jul 14, 2018

  • Applies to:
  • Plesk Automation 11.1
  • Plesk Automation 11.5


Windows service node was added. The below failed task has been generated in the task manager:

"SSH communication error: can not open SCP channel: Invalid ACK response from remote."
The method name was: "taskInstallAgent on SCREF:SharedNodeRegistrator:0"


Failed to execute command 'install_win_sn.exe'. Check 'c:\POA_Deploy' at host '' for more details.


Destination host '' (#6), IP '' : Unable to establish connection with the node #6


Not all required ports were opened or 'pem' service on service node was stopped.


  1. Check that required ports are opened.

  2. Checked connectivity between the service and management nodes, run the checkServiceNode utility on the management node to check possible issues in service node configurations:

    # /usr/local/ppa/bin/check_service_node --ip 
  3. Verify the status of the pem service, make sure that it is running:

    # service pem status

33a70544d00d562bbc5b17762c4ed2b3 e0aff7830fa22f92062ee4db78133079 c1ecc6010feff26cb42d1d14a7881dd6 caea8340e2d186a540518d08602aa065

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