Is anyone parsing with Kapow Software (advice needed)?

Question

Parsing

There is a website: locator.murphyusa.com
I need to get the addresses of stores.
To do this, I make a POST request locator.murphyusa.com/MapServices.asmx/GetLocations
and pass parameters, for example: {"stateAbbr":"FL","filter":null}
But some vegetable, 500 internal error is returned.
Why does this error occur. Am I passing the parameters correctly, how do I know which parameters to pass.
What debugging tools do you use?
Thank you.

Answer 1

www.telerik.com/fiddler