Today SDL Web8.5 installed in new server. I try open CME url first time and got this error "Because SDL Web could not connect to the notification system, it cannot receive push notifications.". Let me know any configuration missing....

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When I open CME got this error: One or more errors occurred.Unexpectedcharacter encountered while parsing value: <. Path '', line 0, position 0. Component: NotificationHub Errorcode: 0 User: NT AUTHORITY\NETWORK SERVICE StackTrace Information Details: at Newtonsoft.Json.JsonTextReader.ParseValue() at Newtonsoft.Json.JsonTextReader.Read() at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadForType(JsonReader reader, JsonContract contract, Boolean hasConverter) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings) at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings) at Microsoft.AspNet.SignalR.Client.Transports.TransportHelper.b__1(String raw) at Microsoft.AspNet.SignalR.TaskAsyncHelper.TaskRunners2.<>c__DisplayClass42.b__41(Task1 t) at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken) at Sdl.SignalR.SignalRMessageBus.SignalRMessageBus.Initialize() at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark) at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) at System.Activator.CreateInstance(Type type, Object[] args) at Sdl.SignalR.Backplane.Common.HubLoader.CreateMessageBus(String assembly, String scaleoutConfigurationType, String scaleoutMessageBusType, Boolean patchOnReceived, Object[] backplaneConfigurationParameters) at Sdl.SignalR.Backplane.Common.HubLoader.Load(IAppBuilder app, String assembly, String scaleoutConfigurationType, String scaleoutMessageBusType, String hubAssemblyName, Boolean patchOnReceived, Object[] backplaneConfigurationParameters) at Tridion.Web.NotificationHub.Startup.Configuration(IAppBuilder app)

Looking recommendation and solution for this issue.

  • 1
    My guess is that you have a firewall policy that is blocking the port on the which the notifications are communicated. Mar 16, 2017 at 0:59
  • it`s working fine in three development server and one SIT server. I check tomorrow morning once second again!!! Mar 16, 2017 at 7:33
  • When I open CME got this error: Mar 16, 2017 at 17:34
  • 1
    you should mention this is a server with Site Minder protection and none of the other servers have it :) Mar 16, 2017 at 22:15
  • It's indeed possible that Site Minder is interfering and returning a different response. You should be able to see that using a network monitoring tool such as Wireshark. Mar 17, 2017 at 9:43

1 Answer 1


This issue occurs SSO enabled CME, To resolve by adjusting the following config values.

[Install Path]SDL Web\hubs\backplaneHub\Web.config

<?xml version="1.0" encoding="utf-8"?>
      <clear />
      <add filePath="..\..\config\Tridion.ContentManager.config" />
    <httpRuntime targetFramework="4.5.2" />
        <remove name="OpenAmModule64" />
        <remove name="SsoAgentHttpModule" />
          checkCertificateRevocationList="false" />

Note: Also, ensure this below URL response is getting 200 response code with javascript output, may be this URL throw 500 error due to SSO enabled.


  • I was facing the same issue in Tridion Sites 9.0 I have made the above changes [Install Path]SDL Web\hubs\NotificationHub\Web.config that resolve the issue, in your answer path is [Install Path]SDL Web\hubs\backplaneHub\Web.config and I have refered this link as well gateway.sdl.com/apex/… alos they mentioned SSO need to be disabled in the notification hub.
    – k951
    Feb 4, 2020 at 13:44

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