SignalR returning 404 on /negotiate -

i'm using signalr - following url works:

signalr/negotiate?clientprotocol=1.5&username=bla&connectiondata=%5b%7b%22name%22%3a%22apphub%22%7d%5d&_=1427859215639

but when cookie expires , user becomes unauthenticated, start getting 404s on request. there way allow requests /signalr not require authentication?

my clientside code:

   if (app.isauthenticated()) {             //start connection.             window.hubready = $.connection.hub.start();    }