Issue: The Subscription Settings service and corresponding application and proxy needs to be running in order to make changes to these settings.

When i was configuring SharePoint 2013 Apps, we need to start the below two services before configuring app URLs,

1. App Management Service
2. Microsoft SharePoint Foundation Subscription Settings Service

after that when i tried to Configure App URLs then i got the below message.

Then i have checked service application. i have found that App Management Service application is created and running but Subscription Setting service application is not created.

And we cannot create service application using UI from central amdin, so we have to create using PowerShell. Here the snippet.

add-pssnapin "Microsoft.Sharepoint.Powershell"

$account = Get-SPManagedAccount <UKREDDY\administrator>

Remove-SPServiceApplicationPool -Identity SettingsServiceAppPool

$appPoolSubSvc = New-SPServiceApplicationPool -Name SettingsServiceAppPool -Account $account

$appSubSvc = New-SPSubscriptionSettingsServiceApplication -ApplicationPool $appPoolSubSvc -Name SettingsServiceApp -DatabaseName SettingsServiceDB

$proxySubSvc = New-SPSubscriptionSettingsServiceApplicationProxy -ServiceApplication $appSubSvc

Now we can see newly created service application and also we can configure app URLs.