Sending Unity Web Request Post returning empty from webhost

iv been stuck on this for a long time and I just can't seem to figure out what the problem is. This is working perfectly if im connecting to http://localhost/ but if I try it on my domain and host online then it suddenly doesn't return any information.

This is my httpPost class:

 public static IEnumerator httpPost(string path, string data, Action<APIHttpRequestModel> callback)
 {

     byte[] bodyRaw = new System.Text.UTF8Encoding().GetBytes(data);
     var www = new UnityWebRequest(path, UnityWebRequest.kHttpVerbPOST);
     
     www.uploadHandler = (UploadHandler)new UploadHandlerRaw(bodyRaw);
     www.downloadHandler = (DownloadHandler)new DownloadHandlerBuffer();
     www.SetRequestHeader("Content-Type", "application/json");

     Debug.Log(www.uploadHandler.data); // This still returns the JSON string it's sending

     yield return www.SendWebRequest();

     if (www.isNetworkError)
     {
         Debug.Log("Something went wrong, and returned error: " + www.error);
         callback(new APIHttpRequestModel(false, 400, www.error));
     } else
     {
         Debug.Log(www.downloadHandler.text); // This returns empty because server isn't receiving any data
         if (www.responseCode == 200)
         {
             callback(new APIHttpRequestModel(true, www.responseCode, www.downloadHandler.text));
             Debug.Log(www.downloadHandler.text);
         }
         else
         {
             callback(new APIHttpRequestModel(false, www.responseCode, www.downloadHandler.text));
             Debug.Log(www.downloadHandler.text);
         }
     }
 }

I've tried debugging and these is what iv found so far:

• If I try to Debug.Log() the www.uploadHandler.data it is populated with data.

  • If I output the request data on the server there is no data getting returned

  • If I try to connect to the same link, on the web host, through a REST Client, it's returning the proper data

  • It definitely is hitting the URL and path specified, but when I try to return the request data, it's just empty.

TL;DR: The code is hitting the endpoint, but not returning data (trying to output the data it sent) on a production server, if I do it locally it's working fine. If I try with a REST client to production server it's working fine aswell.

EDIT 1: I downloaded the latest version of unity and it seems to be working fine there, so it's something related to 2017.3.1f1