API is returning error when using RESTSHARP

So it turns out that because this call was HTTPS i needed to add the following line of code

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;

For .Net 3.5 and 4.0 you could try putting this line of code prior to the initialization of the RestSharp client:

ServicePointManager.SecurityProtocol = (SecurityProtocolType)768 | (SecurityProtocolType)3072;