If a BP Service is deployed in an IIS Application that's bound to multiple domain names or ports, The service may respond with an error. When custom errors are turned off the full error mesage is shown:

This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection. If your service is being hosted in IIS you can fix the problem by setting 'system.serviceModel/serviceHostingEnvironment/multipleSiteBindingsEnabled' to true or specifying 'system.serviceModel/serviceHostingEnvironment/baseAddressPrefixFilters'.

This occurs because WCF can't tell which of the bindings it should respond to. To fix the problem, find the <serviceHostingEnvironment> element in the service's web.config file, and add the bindings WCF should use.

<serviceHostingEnvironment aspNetCompatibilityEnabled="true">
         <add prefix="http://hostname.com/BPServices"/>

At least one prefix must be specified, but you can list more than one if needed.