5151: WAS event failed to send application unconfig to protocol
The IIS World Wide Web Publishing Service is responsible for managing the HTTP protocol and HTTP performance counters. An IIS web site is a unique collection of web pages and web applications that is hosted on an IIS web server.
Event 5151 is generated when Windows Process Activation Service did not send a request to a particular protocol to remove configuration for an application in a site.The protocol, application, and site are specified in the message.
How could you resolve this situation?
Stop and restart the virtual site. This would reestablish the communication between WAS and the protocol for the application.