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[Junos Space] “Device already managed” error while adding new device to Junos Space Network Management Platform



Article ID: KB36107 KB Last Updated: 28 Jul 2020Version: 1.0

This article explains how to add a new device to Junos Space when there is a duplicate entry in the Network Management Platform.



While adding a new device in Junos Space from the Network Management Platform, device discovery fails with the error as “Device already managed”.

The following errors are seen in server.log:

[root@space-0050569ef40e ~]# less /var/log/jboss/servers/server1/server.log | grep -i duplication

2019-11-04 06:57:46,024 ERROR [] (Thread-1760 (HornetQ-client-global-threads-2038299044)) Discovery failed for device with IP : Serial number [CY4317AF0956] duplication. Device already managed 

2019-11-04 06:57:46,049 ERROR [] (Thread-1760 (HornetQ-client-global-threads-2038299044)) Send failure message for add reachable device with ip failed --- Device is already managed

The error logs indicate the presence of a duplicate serial number entry.

Note: If the highlighted message is not found in Junos Space CLI logs, it could be that a different issue has occurred. Contact Support for assistance.


  • This issue occurs due to a duplicate serial number entry for a device that was previously managed and decommissioned from Junos Space.

  • The issue may also occur because of a duplicate serial number entry for a device that has been cloned from another virtual device.



To troubleshoot, perform the following:

  1. Check the Serial Number of the device that failed to be discovered in Junos Space.​ Refer to KB17568 - [SRX] How to find the serial number of my SRX device to find the serial number of the SRX device.

  2. Log in to Junos Space WebUI and navigate to Network Management Platform >> Devices >> Device Management. Check/search for the duplicate Serial Number entry on the search bar. 

Note: Remember to search for the device serial number across all domains created in Junos Space.

  1. You can also create a filter for the “Serial Number” on the Device Management tab.

  1. If you find any device on the Device Management tab with the duplicate Serial Number, check/confirm with the customer and proceed to delete that device entry.

  2. Re-discover the device. This time it should get detected and added successfully.


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