The HTTP service is to busy: (503) Server Unavailable. (4293772)

Issue
Error in AS UI:
Errors in Event log:

Microsoft-Windows-IIS-W3SVC-WP  
Provider Name="Microsoft-Windows-IIS-W3SVC-WP" Guid="{670080D9-742A-4187-8D16-41143D1290BD}" EventSourceName="W3SVC-WP"
Event ID: 2281
Microsoft-Windows-IIS-W3SVC-WP  
Provider Name="Microsoft-Windows-IIS-W3SVC-WP" Guid="{670080D9-742A-4187-8D16-41143D1290BD}" EventSourceName="W3SVC-WP"
Event ID: 2276
Microsoft-Windows-WAS                                             
Provider Name="Microsoft-Windows-WAS" Guid="{524B5D04-133C-4A62-8362-64E8EDB9CE40}" EventSourceName="WAS"
Event ID: 5002

Error in webui log:

[2014-05-16 09:46:02Z] [ 1328] [    7] [ERROR] [                             ExecuteScheduledTasks] Error while executing scheduled tasks: {0} Void HandleReturnMessage(System.Runtime.Remoting.Messaging.IMessage, System.Runtime.Remoting.Messaging.IMessage)
 The HTTP service located at http://localhost/asws/ArchiveShuttle.svc is too busy.
 Server stack trace:
    at System.ServiceModel.Channels.HttpChannelUtilities.ProcessGetResponseWebException(WebException webException, HttpWebRequest request, HttpAbortReason abortReason)
    at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)
    at System.ServiceModel.Channels.RequestChannel.Request(Message message, TimeSpan timeout)
    at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)
    at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)
    at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)
 Exception rethrown at [0]:
    at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
    at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
    at ArchiveShuttle.Core.Service.ArchiveShuttleClient.IArchiveShuttle.ExecuteScheduledTasks()
    at ArchiveShuttle.Core.Service.ModuleCommunication.ExecuteScheduledTasks(Object sender, ElapsedEventArgs elapsedEventArgs)
 System.Net.WebResponse GetResponse()
 The remote server returned an error: (503) Server Unavailable.
    at System.Net.HttpWebRequest.GetResponse()
    at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout)

Solution
In IIS on the ArchiveShuttleWSAppPool, right click -> Advanced Settings
On the “Rapid-Fail Protection” section:

• Set “Failure Interval (minutes)” to 1
• Set “Maximum Failures” to 10

As the last step reset IIS.