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Article ID: 113454, created on Mar 14, 2012, last review on May 17, 2015

  • Applies to:
  • Operations Automation 5.x
  • Operations Automation 2.x


Parallels Plesk Panel initialization task fails with the error: unknown protocol, as in the example below:

Task ID    274160
Queue name    vps_operations_192
Task name    Plesk in VPS 192: initial setup
Task description    perform initial setup of Plesk
Queue status    Rescheduled    
Start not earlier than    Mar-14-2012 08:50
Method name    performInitialSetup on SCREF:PleskBridge:0
Last execution output    https://IP_ADDRESS:8443/enterprise/control/agent.php : error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol

Sometimes you can see another error message:
Unknown SSL protocol error in connection to IP_Address:8008, like at the example:

Task ID 274165
Queue name      vps_operations_192
Task name       Plesk on vps-192.domain.tld: register IP-address 'IP_ADDRESS' in Plesk
Task description        Plesk on vps-192.domain.tld: register IP-address 'IP_ADDRESS' in Plesk
Queue status    Failed   
Start not earlier than  Mar-14-2012 08:50
Method name     registerIP on SCREF:PleskBridge:0
Last execution output    https://IP_ADDRESS:8443/enterprise/control/agent.php : Unknown SSL protocol error in connection to IP_ADDRESS:8008


There are several possible reasons for this error:
  1. PVC container cannot be reached by the assigned IP address.
  2. Connection to the port 8443 is blocked.
  3. Parallels Plesk Panel installation failed.


POA communicates with Parallels Plesk Panel installed inside a PVC container through the PrivacyProxy server using Plesk API.

1. Make sure that the assigned IP address on the container is reachable from the PrivacyProxy server and that the connection to the port 8443 is not blocked on either server: PVC container with Parallels Plesk Panel or PrivacyProxy.
To check the connection login on the PrivacyProxy server and to check the connection to the PVC container on port 8443 with the telnet command:
# telnet 8443
Connected to
Escape character is '^]'.

2. Check if Parallels Plesk Panel is successfully installed inside the PVC container. All tasks prior to the task "Initial setup" should be successfully completed, and no tasks related to this container should be cancelled.

If the task "Install set of VZ templates to VPS VPS_hostname" was completed, check if you can browse the URL https://IP_ADDRESS:8443. You should be able to see the Parallels Plesk Panel login page.

If you cannot see Parallels Plesk Panel login page check the overall Parallels Plesk Panel status using the article:

How do I check if Parallels Plesk Panel for Linux is functioning properly?

How do I check if Parallels Plesk Panel for Windows is functioning properly?

3. Check if the service template is configured correctly.

How to create service template for PVC containers with Parallels Plesk Panel provisioning

Additional information

Use the following article to find out where the PrivacyProxy service is installed.

How to find out host(s) where particular service is installed

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