Unity Realtime GameLift Client not working with IL2CPP build


I can create a connection to my realtime server uses lambda calls when I build a Unity project that uses Mono as its scripting backend, but when I build via IL2CPP, which I need to if I want to build with Universal Windows Platform (VR use), my code no longer works. I can even get this code to work from a UWP platform if I only run it from the Unity Editor. All of that to me suggests it has to do solely with it being an IL2CPP build.

My code:

InvokeResponse invokeResponse = null;
       invokeResponse = await _client.InvokeAsync(_request);
catch (Exception _exception)
      Debug.LogError("INSIDE CATCH: " + invokeResponse?.FunctionError + _exception);
      GetInstance().QForMainThread(AddErrorText, invokeResponse?.FunctionError + _exception.ToString());

The try always fails with IL2CPP with the error:
System.Net.Http.HttpRequestException: An error occurred while sending the request —> System.Net.WebException: Error: ConnectFailure (Value does not fall within the expected range.) —> System.ArgumentException: Value does not fall within the expected range.

Full Stack Trace is too large to enter in, so it is attached as a .txt file.
FullStackTrace.txt (588.3 KB)
I do have a link.xml file in my Assets folder and it is set up as follows:

  	<!-- if you are using AWSConfigs.HttpClient.UnityWebRequest option-->

  <assembly fullname="UnityEngine">
  	<type fullname="UnityEngine.Networking.UnityWebRequest" preserve="all" />
  	<type fullname="UnityEngine.Networking.UploadHandlerRaw" preserve="all" />
  	<type fullname="UnityEngine.Networking.UploadHandler" preserve="all" />
  	<type fullname="UnityEngine.Networking.DownloadHandler" preserve="all" />
  	<type fullname="UnityEngine.Networking.DownloadHandlerBuffer" preserve="all" />
  <assembly fullname="mscorlib">
  	<namespace fullname="System.Security.Cryptography" preserve="all"/>

  <assembly fullname="System">
  	<namespace fullname="System.Security.Cryptography" preserve="all"/>

  <assembly fullname="AWSSDK.Core" preserve="all">
  	<namespace fullname="Amazon.Util.Internal.PlatformServices" preserve="all"/>
  <assembly fullname="AWSSDK.CognitoIdentity" preserve="all"/>
  <assembly fullname="AWSSDK.SecurityToken" preserve="all"/>
  <assembly fullname="AWSSDK.Lambda" preserve="all"/>

Any help with this error would be greatly appreciated! Let me know if you need more information to help track down what’s going on.