Azure Servicebus WCF Relay, Address is already in use by an existing listener with different settings

Question

I'm trying to get an Azure Servicebus WCF relay to work following this tutorial: https://learn.microsoft.com/en-us/azure/service-bus-relay/service-bus-relay-tutorial

While following the steps I ran into this exception: System.ServiceModel.AddressAlreadyInUseException

In this case the exception message was "This endpoint requires IsDynamic = False". That I could fix by explicitly setting this property to false.

After this fix still the same AddressAlreadyInUseException

However the message now changed to "Address sb://[namespace].servicebus.windows.net/[WCF Relay name] is already in use by an existing listener with different settings"

I really can't understand where this error comes from, as it's a newly created WCF Relay endpoint and no other listeners are running. What could be causing this?

Answer 1

• Are you creating a WCF Relay explicitly in the portal (or with NamespaceManager.CreateRelay[Async]) for this endpoint? If so, then you need the binding's IsDynamic == false). If you're not pre-creating the endpoint then the binding's IsDynamic must be true.
• Are you using NetTcpRelayBinding or some other relay binding?
• If you try again after ~30 minutes do you get the same errors?
• If you try with a different WCF Relay(endpoint) address do you see the same behavior?

Answer 2

We just had this happen for a really strange reason so am posting here in case it helps anyone else.

Someone configured a tenant with a service path of ./. This made it so the root path was taken and then every tenant that tried to register would get the error "Address sb://[namespace].servicebus.windows.net/[WCF Relay name] is already in use by an existing listener with different settings". When we turned off the bad endpoint all the other endpoint were able to work again.