Could not connect to the notification hub

Question

We installed SDL Tridion Sites 9.1 on Azure VM using Microsoft Azure SQL database 12.0. initially, we were getting "The SQL Server edition of the target server is unsupported, e.g. SQL Azure." which was fixed after updating signalrBackplaneHub element in Tridion config file

<signalrBackplaneHub messageBusType="Microsoft.AspNet.SignalR.ServiceBus.ServiceBusMessageBus" scaleoutConfigurationType="Microsoft.AspNet.SignalR.ServiceBusScaleoutConfiguration" assembly="Microsoft.AspNet.SignalR.ServiceBus3, Version=2.4.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
    <backplaneConnectionParameters>
      <add parameter="Endpoint=Endpoint"/>
      <add parameter="topicPrefix"/>
    </backplaneConnectionParameters>
  </signalrBackplaneHub>

After restarting we are getting below error now. what could be missing

Error: No transport could be initialized successfully. Try specifying a different transport or none at all for auto initialization.

Answer 1

Please refer to this article for more information Link

suggest to ensure that the Scale settings for Azure message bus set to Standard (rather than Basic). In addition the behavior is described as follows: If there is an established connection between Notification and Backplane hubs, it should look something like:

http://.../hubs/notificationHub/signalr/start?transport=longPolling&clientProtocol=1.5&connectionToken="token"

This error might be thrown on the very first Content Manager Explorer load when internally the notification hub is not initialized, however it does get initialized a shortly after. To see this behavior refer to the Network Tab in the browser