Symptoms

We'd like to add service instance in Endpoints WebService but unfortunately error message showed up.
The message : VALIDATIONThe remote server return an error. (500) Internal Server Error. SourceCode.SmartObjects.Services.Management.
 

Diagnoses

Web service URL is not correct. Web service URL is not correct. A standard web service URL should be something in this format:

http://://?wsdl
 

Resolution

Changed the Web service URL