Power BI Report Server upload error

More from the log:

2017-05-30 10:16:08.7856|INFO|1|Setting up Hosted Process State
2017-05-30 10:16:08.7856|INFO|1|CFG : rsConfigFilePath = [C:\Program Files\Microsoft Power BI Report Server\PBIRS\ReportServer\rsreportserver.config] (env)
2017-05-30 10:16:08.7856|INFO|1|Attempting to read Configuration from file C:\Program Files\Microsoft Power BI Report Server\PBIRS\ReportServer\rsreportserver.config -> C:\Program Files\Microsoft Power BI Report Server\PBIRS\ReportServer\rsreportserver.config
2017-05-30 10:16:09.0677|FATAL|1|Could not start PBIXSystem.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Net.HttpListenerException: Access is denied
   at System.Net.HttpListener.AddAllPrefixes()
   at System.Net.HttpListener.Start()
   at Microsoft.Owin.Host.HttpListener.OwinHttpListener.Start(HttpListener listener, Func`2 appFunc, IList`1 addresses, IDictionary`2 capabilities, Func`2 loggerFactory)
   at Microsoft.Owin.Host.HttpListener.OwinServerFactory.Create(Func`2 app, IDictionary`2 properties)
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at Microsoft.Owin.Hosting.ServerFactory.ServerFactoryAdapter.Create(IAppBuilder builder)
   at Microsoft.Owin.Hosting.Engine.HostingEngine.Start(StartContext context)
   at Microsoft.PowerBI.ReportServer.WebHost.Program.Main()