All 3 minutes: Warning Event ID 1310

Every 3 minutes I get this Warning in the log:

Event code: 3008
Event message: A configuration error has occurred.
Event time: 28-8-2014 19:31:59
Event time (UTC): 28-8-2014 17:31:59
Event ID: 325917491c9845889420b93d70a37315
Event sequence: 12740
Event occurrence: 12739
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/2/ROOT-1-130533385777588951
    Trust level: Full
    Application Virtual Path: /
    Application Path: C:\inetpub\wwwroot\
    Machine name: ITSPECSRV
 
Process information:
    Process ID: 27212
    Process name: w3wp.exe
    Account name: IIS APPPOOL\DefaultAppPool
 
Exception information:
    Exception type: ConfigurationErrorsException
    Exception message: It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level.  This error can be caused by a virtual directory not being configured as an application in IIS. (C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess\owa\web.config line 84)
   at System.Configuration.ConfigurationSchemaErrors.ThrowIfErrors(Boolean ignoreLocal)
   at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject)
   at System.Configuration.BaseConfigurationRecord.GetSection(String configKey)
   at System.Web.Configuration.RuntimeConfig.GetSectionObject(String sectionName)
   at System.Web.Configuration.RuntimeConfig.GetSection(String sectionName, Type type, ResultsIndex index)
   at System.Web.Configuration.RuntimeConfig.get_Identity()
   at System.Web.HttpContext.SetImpersonationEnabled()
   at System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context)

 
 
Request information:
    Request URL: http://localhost:81/Exchange
    Request path: /Exchange
    User host address: ::1
    User: 
    Is authenticated: False
    Authentication Type: 
    Thread account name: IIS APPPOOL\DefaultAppPool
 
Thread information:
    Thread ID: 6
    Thread account name: IIS APPPOOL\DefaultAppPool
    Is impersonating: False
    Stack trace:    at System.Configuration.ConfigurationSchemaErrors.ThrowIfErrors(Boolean ignoreLocal)
   at System.Configuration.BaseConfigurationRecord.GetSectionRecursive(String configKey, Boolean getLkg, Boolean checkPermission, Boolean getRuntimeObject, Boolean requestIsHere, Object& result, Object& resultRuntimeObject)
   at System.Configuration.BaseConfigurationRecord.GetSection(String configKey)
   at System.Web.Configuration.RuntimeConfig.GetSectionObject(String sectionName)
   at System.Web.Configuration.RuntimeConfig.GetSection(String sectionName, Type type, ResultsIndex index)
   at System.Web.Configuration.RuntimeConfig.get_Identity()
   at System.Web.HttpContext.SetImpersonationEnabled()
   at System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context)
 
 
Custom event details:

I have no idea what's wrong. Everything works as should. Can I ignore these warnings?

Leo