EWS editor is open source software with below 3 main goals,
- Demonstrate the Exchange Web Services Managed API functionality and simplicity to developers through its source code.
- Demonstrate the Exchange Web Services SOAP traffic used to perform actions initiated through an explorer user interface.
- Assist non-developers in debugging and understanding Exchange stores by exploring items, folders, and their properties in depth.
The below link contains some valuable information about how a user can use the EWS Editor tool to check EWS connection related problems.