SignalR 2.2.0 WebSocket error connecting to hub

Question

I have an ASP.Net MVC application that I have added SignalR to. After following the "Getting Started" tutorial (with modifications of course since it's going in my application) I got it working on localhost. However once it's in the production environment, I get the following error:

WebSocket connection to 'ws://xxxxx/signalr/connect?transport=webSockets&clientProtocol=1.5&connectionToken=xxxxx' failed: Connection closed before receiving a handshake response.

I can access /signalr/hubs (I get a js file). Any ideas as to why this would happen?

Answer 1

This may be due to the fact that your web server doesn't support WebSockets (IIS 7.5, for instance. It may also be due to the fact that you are using a "proxy" server like ARR and it just cannot "route" WebSocket requests.

The first thing I would try to do is to disable WebSockets on SignalR, just as a debug tool. Here's how: SignalR - How do I disable WebSockets

If your problem persists, it's a general SignalR problem but at least you will have a more specific error. If the problem stops, now you know it is a server issue.