Submit a ticketCall us

whitepaperYour VM Perplexities Called, and They Need You to Read This.

Virtualization can give you enormous flexibility with future workloads and can be a key enabler for other areas, like cloud computing and disaster recovery. So, how can you get a handle on the performance challenges in your virtual environment and manage deployments without erasing the potential upside? Learn the four key areas you need to be focusing on to help deliver a healthy and well-performing data center.

Get your free white paper.

Home > Success Center > VoIP & Network Quality Manager (VNQM) > VNQM - Knowledgebase Articles > VNQM Business Layer failed to start

VNQM Business Layer failed to start

Updated August 16, 2018



The following message appears after upgrading VNQM to 4.2.4. 


VNQM Business Layer" failed to start on [Servername]. Please restart the Module Engine service on [Servername]


When this happens, issues such as adding a Call Manager, IPSLA operation in unknown status will occur. This is because the IPSLA business layer is failing.


Looking at IPSLA BusinessLayer log, it will show these error messages.


2016-06-16 19:01:12,099 [7] ERROR BusinessLayer.Plugin (null) - IP SLA Monitor service [SERVERNAME] failed to start. 

System.ArgumentException: An item with the same key has already been added.

   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)

   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)

   at SolarWinds.Orion.IpSla.BusinessLayer.ServiceMonitor.UpdateEngines()

   at SolarWinds.Orion.IpSla.BusinessLayer.ServiceMonitor.Start()

   at SolarWinds.Orion.IpSla.BusinessLayer.VoipBusinessLayerPlugin.Start()

2016-06-16 19:31:10,455 [Scheduler] ERROR SolarWinds.Common.Utility.ScheduledTask (null) - OptimizePollingJobExecution threw an exception.

System.ObjectDisposedException: Cannot access a disposed object.

Object name: 'SolarWinds.Orion.IpSla.Polling.Poller'.




  • VNQM 4.2
  • VNQM 4.2.X
  • VNQM 4.4.x




  • Either a dll was improperly placed in the correct directory or in an additional directory, or the voipjobinfo table has duplicate entries.
  • Error in the ipsla.businesslayer.log is indicative that it is attempting to process a job that is either missing or duplicated from the voipjobinfo table in the database.



1.  Stop all Orion services on all pollers

2. Check through the directory of Program Files (x86)\SolarWinds Orion\Voip Monitor. Find any .dll files that are duplicated, renamed to any other variation (.old, .bak or .old.dll, etc) and remove it from that directory. You can also check the directory above that one to see if the files exist anywhere else.

3. Backup your SQL Database before making any changes to the database.

4. Use the steps to run following SQL query  Running SQL query Orion Database Manager 


Truncate Table VoipJobInfo


5. Reinstall rebuild Solarwinds Collector on all pollers

6. Reinstall rebuild Solarwinds Job Engine v2 on all pollers

7. Reinstall the JobEngine.msi on all pollers

8. Start all Orion Services on all pollers

Please make sure everything is running 




Last modified