Cross-domain does not work with signalr 2.0

Question

I have a signalr 2.0 server that should serve the multiple domains.. So in need to enable CORS in my server. I user iis7.5 as web server. I enabled the CORS in Startup method of my project as follows

 public void Configuration(IAppBuilder app)
        {
        app.Map("/signalr", map =>
            {
                // Setup the CORS middleware to run before SignalR.
                // By default this will allow all origins. You can 
                // configure the set of origins and/or http verbs by
                // providing a cors options with a different policy.
                map.UseCors(CorsOptions.AllowAll);
                var hubConfiguration = new HubConfiguration
                {
                    // You can enable JSONP by uncommenting line below.
                    // JSONP requests are insecure but some older browsers (and some
                    // versions of IE) require JSONP to work cross domain
                    // EnableJSONP = true
                };
                // Run the SignalR pipeline. We're not using MapSignalR
                // since this branch already runs under the "/signalr"
                // path.
                map.RunSignalR(hubConfiguration);
}
}

This code is copy and pasted from this article http://www.asp.net/signalr/overview/signalr-20/hubs-api/hubs-api-guide-javascript-client

I created a localhost project and try to connect to signalr server.

But I get the following error in firefox

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://MyWebSite.com:8082/signalr/negotiate?connectionData=%5B%7B%22name%22%3A%22sahragostarhub%22%7D%5D&clientProtocol=1.3&_=1405622027746 This can be fixed by moving the resource to the same domain or enabling CORS. negotiate

and this error in chrome XMLHttpRequest cannot load http://MyWebSite.com:8082/signalr/negotiate?connectionData=%5B%7B%22name%22%3A%22sahragostarhub%22%7D%5D&clientProtocol=1.3&_=1405622032883. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '(My Client site address)' is therefore not allowed access

I Also add the following lines to my web.config

 <httpProtocol>
      <customHeaders>
        <clear />
       <add name="Access-Control-Allow-Origin" value="*" />
      </customHeaders>
    </httpProtocol>

This change was also useless.

Answer 1

Try removing WebDAV module in your configuration (helped me some time ago):

<configuration>              
    <system.webServer>                   
        <modules>
            <remove name="WebDAVModule" />
...

Answer 2

I experienced this today, and after poking around a bit, found that the installing the Microsoft.Owin.Cors package resolved the issue for me.

Just run the following command in the Package Manager Console:

Install-Package Microsoft.Owin.Cors

Build, and reload the page.