2.2.3.2.3 Errors
If the license request is refused after a silent request, the server returns any HTTP error status code that is returned to the higher layer. The higher layer then attempts nonsilent acquisition.
If the license request is refused after a nonsilent request, the license server responds with a user-visible HTML page. It is suggested to display an explanation of what the error condition was and why it was encountered.
There is no comprehensive set of errors. Protocol implementations will want to coordinate custom client and custom server implementations to handle their own custom error codes.