Base on your sample i got 404 and the following message:
posting to api/ratesquery
{
"Message": "No HTTP resource was found that matches the request URI 'http://api.gosweetspot.com/api/ratesquery'."
}
I also tried RatesQueryV1/availablerates in your sample application and it response with 200 but response payloads are empty objects (see following).
{"Available":[],"Rejected":[],"ValidationErrors":{}}
Is this endpoint actually working?