My SOAP Operation is returning an error "ERROR
The SOAP operation is trying to send message to host "PKB_SOAP_Sender" (e.g check if you are using API SendRequestSync/SendRequestAsync ("PKB_SOAP_Sender",...) in your code) which is not a registered host or part of the production.
Thanks Suriya. I realised I had created the Operation as " "PKB_Soap_Sender" but was calling it as "PKB_SOAP_Sender"!
Your comment made me look closer so I could see this.