We are having exactly the same issue with SIGNALR. Those query notification errors:
The query notification dialog on conversation handle '{104A6FA1-3435-F011-A77F-D4F5EF146118}.' closed due to the following error: '<?xml version="1.0"?><Error xmlns=http://schemas.microsoft.com/SQL/ServiceBroker/Error>-8490<Description>Cannot find...