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Skype for Business Backup Service Fail to Start

This will only take a second. While reinstalling my lab on CU4 I couldn’t start the Skype for Business Backup Service. Deployment logs showed successful deployment but when the service attempted to start I received an Error 4006 on the LS Backup Service.

The full error was:

Skype for Business Server 2015, Backup Service service could not be started.

Exception information: System.ServiceModel.AddressAccessDeniedException: HTTP could not register URL https://+:443/BackupService/mex/. Your process does not have access rights to this namespace (see http://go.microsoft.com/fwlink/?LinkId=70353 for details). —> System.Net.HttpListenerException: Access is denied
at System.Net.HttpListener.AddAllPrefixes()
at System.Net.HttpListener.Start()
at System.ServiceModel.Channels.SharedHttpTransportManager.OnOpen()
— End of inner exception stack trace —
at System.ServiceModel.Channels.SharedHttpTransportManager.OnOpen()
at System.ServiceModel.Channels.TransportManager.Open(TransportChannelListener channelListener)
at System.ServiceModel.Channels.TransportManagerContainer.Open(SelectTransportManagersCallback selectTransportManagerCallback)
at System.ServiceModel.Channels.HttpChannelListener`1.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.Dispatcher.ChannelDispatcher.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.ServiceHostBase.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at Microsoft.Rtc.BackupService.BackupServiceWorker.StartWcfHost()
at Microsoft.Rtc.BackupService.BackupServiceWorker.StartServer().
Cause: Startup errors.
Check the events prior to this to resolve the service startup issue.

So this is a ACL issue on a listener.

Using netsh we can pull the reservation list for the backup service URL using the following command

netsh http show urlacl url=https://+:443/BackupService.mex/

The command showed that no reservations had been set


The service is run using the NETWORK SERVICE account, and the acl needs to be set with this account to work.

To do this run the following command

netsh http add urlacl=https://+:443/BackupService.mex/ user=”NETWORK SERVICE”


Repeat the show command to view the new ACL


Now start the backup service and all should be fine


Running Get-CsBackupServiceStatus –PoolFQDN <fe1.domain.com> returns normal state


and the same for the backup server


Final test to Invoke-CsBackupServiceSync –PoolFqdn fe1.domain.com

All good from Primary


And from Secondary



  1. When you installed, did you let the installer check online for Updates, and in doing so it deployed CU4? Just wondering because I had a similar ACL issue with a CU3 deployment. I think I may be going back to the long method, deploy on RTM and then Patch up to CU4, I’m thinking there’s possibly an issue with the Install-to-latest-CU process where perhaps IIS isn’t ready.

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