Visual Studio & Material Issue & REST

Ok, so, I have managed to get a bit further, using josecgomez code after the response code i could see i was missing some parameters.
I am now getting a different error, not sure if it is because I am using a custom method?

{
  "RequestURI": "https://kinetic/KineticTest/api/V1/Erp.BO.IssueReturnSvc/GetNewIssueReturn",
  "Response": {
    "Request": {
      "AlwaysMultipartFormData": false,
      "MultipartFormQuoteParameters": false,
      "FormBoundary": null,
      "Parameters": [
        {
          "Name": "License",
          "Value": "{\"ClaimedLicense\":\"00000003-b615-4300-957b-34956697f040\"}",
          "Type": 2,
          "Encode": false,
          "ContentType": null
        },
        {
          "Name": "cache-control",
          "Value": "no-cache",
          "Type": 2,
          "Encode": false,
          "ContentType": null
        },
        {
          "Name": "authorization",
          "Value": "Basic dHJhY3ljOlNwNHJrbGVz",
          "Type": 2,
          "Encode": false,
          "ContentType": null
        },
        {
          "Name": "contextheader",
          "Value": "{\"Context\":{\"BpmData\":[{\"Password\":\"\",\"ButtonValue\":0,\"Character01\":\"\",\"Character02\":\"\",\"Character03\":\"\",\"Character04\":\"\",\"Character05\":\"\",\"Character06\":\"\",\"Character07\":\"\",\"Character08\":\"\",\"Character09\":\"\",\"Character10\":\"\",\"Character11\":\"\",\"Character12\":\"\",\"Character13\":\"\",\"Character14\":\"\",\"Character15\":\"\",\"Character16\":\"\",\"Character17\":\"\",\"Character18\":\"\",\"Character19\":\"\",\"Character20\":\"\",\"Number01\":0.0,\"Number02\":0.0,\"Number03\":0.0,\"Number04\":0.0,\"Number05\":0.0,\"Number06\":0.0,\"Number07\":0.0,\"Number08\":0.0,\"Number09\":0.0,\"Number10\":0.0,\"Number11\":0.0,\"Number12\":0.0,\"Number13\":0.0,\"Number14\":0.0,\"Number15\":0.0,\"Number16\":0.0,\"Number17\":0.0,\"Number18\":0.0,\"Number19\":0.0,\"Number20\":0.0,\"Checkbox01\":false,\"Checkbox02\":false,\"Checkbox03\":false,\"Checkbox04\":false,\"Checkbox05\":false,\"Checkbox06\":false,\"Checkbox07\":false,\"Checkbox08\":false,\"Checkbox09\":false,\"Checkbox10\":false,\"ShortChar01\":\"\",\"ShortChar02\":\"\",\"ShortChar03\":\"\",\"ShortChar04\":\"\",\"ShortChar05\":\"\",\"ShortChar06\":\"\",\"ShortChar07\":\"\",\"ShortChar08\":\"\",\"ShortChar09\":\"\",\"ShortChar10\":\"\",\"SysRowID\":\"72e33225-42c6-495e-b339-b31166769288\",\"RowMod\":\"\"}],\"Client\":[{\"ClientType\":\"EPICOR_REST_CLIENT\",\"ProcessId\":\"\",\"AssemblyName\":\"\",\"CustomizationId\":\"\",\"CurrentUserId\":\"tracyc\",\"CurrentCompany\":\"COMP01\",\"SysRowID\":\"91cca06c-f2cd-4673-9a49-509fdc992a58\"}]}}",
          "Type": 2,
          "Encode": false,
          "ContentType": null
        },
        {
          "Name": "X-API-Key",
          "Value": "v5YSazXmtgABwjSutjM4bRMT06Sf4wsKIxhThafgLLS5P",
          "Type": 2,
          "Encode": false,
          "ContentType": null
        },
        {
          "DataFormat": 3,
          "ContentEncoding": null,
          "Name": "",
          "Value": "{\"Company\":\"COMP01\",\"TranQty\":30,\"ToJobNum\":\"1177333\",\"ToAssemblySeq\":0,\"ToJobSeq\":30,\"pcTranType\":\"STK-MTL\",\"pcMtlQueueRowID\":\"00000000-0000-0000-0000-000000000000\",\"pCallProcess\":\"IssueMaterial\",\"ds\":\"Erp.Tablesets.IssueReturn\"}",
          "Type": 3,
          "Encode": false,
          "ContentType": "application/json"
        }
      ],
      "Files": [],
      "Method": 1,
      "Timeout": 0,
      "Resource": "https://kinetic/KineticTest/api/V1/Erp.BO.IssueReturnSvc/GetNewIssueReturn",
      "RequestFormat": 0,
      "RootElement": null,
      "OnBeforeDeserialization": null,
      "OnBeforeRequest": null,
      "OnAfterRequest": null,
      "Attempts": 1,
      "CompletionOption": 0,
      "ResponseWriter": null,
      "AdvancedResponseWriter": null
    },
    "ContentType": "text/plain",
    "ContentLength": 123,
    "ContentEncoding": [],
    "Content": "Sorry! Something went wrong. Please contact your system administrator. Correlation Id: 0ca94cdc-bb31-4305-b97c-9ce78ccceb1d",
    "StatusCode": 500,
    "IsSuccessStatusCode": false,
    "IsSuccessful": false,
    "StatusDescription": "Internal Server Error",
    "RawBytes": "U29ycnkhIFNvbWV0aGluZyB3ZW50IHdyb25nLiBQbGVhc2UgY29udGFjdCB5b3VyIHN5c3RlbSBhZG1pbmlzdHJhdG9yLiBDb3JyZWxhdGlvbiBJZDogMGNhOTRjZGMtYmIzMS00MzA1LWI5N2MtOWNlNzhjY2NlYjFk",
    "ResponseUri": "https://kinetic/KineticTest/api/V1/Erp.BO.IssueReturnSvc/GetNewIssueReturn",
    "Server": "",
    "Cookies": [],
    "Headers": [
      {
        "Name": "Pragma",
        "Value": "no-cache",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      },
      {
        "Name": "Transfer-Encoding",
        "Value": "chunked",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      },
      {
        "Name": "Telemetry",
        "Value": "{\"TelemetryKey\":\"bc19332c-15b1-48a7-b777-6e31dbc2823f\",\"Telemetry\":true}",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      },
      {
        "Name": "CallInfo",
        "Value": "{\"CorrelationId\":\"0ca94cdc-bb31-4305-b97c-9ce78ccceb1d\"}",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      },
      {
        "Name": "Cache-Control",
        "Value": "no-store, no-cache",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      },
      {
        "Name": "Date",
        "Value": "Wed, 06 Mar 2024 10:08:14 GMT",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      }
    ],
    "ContentHeaders": [
      {
        "Name": "Content-Type",
        "Value": "text/plain",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      },
      {
        "Name": "Expires",
        "Value": "-1",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      },
      {
        "Name": "Content-Length",
        "Value": "123",
        "Type": 2,
        "Encode": false,
        "ContentType": null
      }
    ],
    "ResponseStatus": 2,
    "ErrorMessage": null,
    "ErrorException": {
      "ClassName": "System.Net.Http.HttpRequestException",
      "Message": "Request failed with status code InternalServerError",
      "Data": null,
      "InnerException": null,
      "HelpURL": null,
      "StackTraceString": null,
      "RemoteStackTraceString": null,
      "RemoteStackIndex": 0,
      "ExceptionMethod": null,
      "HResult": -2146233088,
      "Source": null,
      "WatsonBuckets": null,
      "SafeSerializationManager": {
        "m_serializedStates": [
          {}
        ]
      },
      "CLR_SafeSerializationManager_RealType": "System.Net.Http.HttpRequestException, System.Net.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
    },
    "Version": {
      "Major": 1,
      "Minor": 1,
      "Build": -1,
      "Revision": -1,
      "MajorRevision": -1,
      "MinorRevision": -1
    },
    "RootElement": null
  },
  "ResponseData": null,
  "ResponseBody": "Sorry! Something went wrong. Please contact your system administrator. Correlation Id: 0ca94cdc-bb31-4305-b97c-9ce78ccceb1d",
  "BLException": null,
  "BadRequest": null,
  "ResponseStatus": 500,
  "RestCallException": {
    "ClassName": "Newtonsoft.Json.JsonReaderException",
    "Message": "Unexpected character encountered while parsing value: S. Path '', line 0, position 0.",
    "Data": null,
    "InnerException": null,
    "HelpURL": null,
    "StackTraceString": "   at Newtonsoft.Json.JsonTextReader.ParseValue()\r\n   at Newtonsoft.Json.JsonTextReader.Read()\r\n   at Newtonsoft.Json.JsonReader.ReadForType(JsonContract contract, Boolean hasConverter)\r\n   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent)\r\n   at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)\r\n   at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings)\r\n   at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings)\r\n   at EpicorRestAPI.EpicorRest.GetEpicorResponseObject(Uri baseUri, RestResponse response)",
    "RemoteStackTraceString": null,
    "RemoteStackIndex": 0,
    "ExceptionMethod": "8\nParseValue\nNewtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed\nNewtonsoft.Json.JsonTextReader\nBoolean ParseValue()",
    "HResult": -2146233088,
    "Source": "Newtonsoft.Json",
    "WatsonBuckets": null
  },
  "RestSharpErrorMessage": null,
  "ResponseError": "Unexpected character encountered while parsing value: S. Path '', line 0, position 0.",
  "IsErrorResponse": true
}

The program ‘[22624] WindowsFormsApp2.exe’ has exited with code 4294967295 (0xffffffff).