You should never get a HTTP 500 error in normal operation mode. There are two causes for HTTP 500 errors:
1. A major problem on our side
2. A problem with your request.

The first thing you should do is examine possible problems with your request. 

Missing Required Parameters: All parameters with a non-string data type are required . This includes numerics, dates, booleans, and enumerations (which are really numerics). Only missing string values will not cause an HTTP 500 error.
Mis-typed Enumerations: Enumerations are case-sensitive. Make sure you look at the list of valid values in the SOAP, GET or POST description. Our test form makes it easy by using drop-downs but your code must be correct. For instance, you may get the following response if you omit an integer parameter: "System.ArgumentException: Cannot convert to System.Int32" .

If your request is valid and the problem persists, please reach out support@xignite.com