Validating a certificate in Hololens

I am currently building a project for Hololens, using Visual Studio and Unity3D. This project uses external dll's, among which RestSharp and Manatee.Json. My application uses those libraries to make calls to Trello's API in C#.

Curently, my project runs perfectly on Unity's "Play mode". However, when I try to build the project, I get the following error :

 Assets\Scripts\Controller\RestController.cs(25,9): error CS0103: The name 'ServicePointManager' does not exist in the current context

Here is the incriminated line :

 ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };

I believe I get the error because ServicePointManager is not part of .net Core, which is my build target.

I tried removing this line entirely, and the project manages to build properly. However, at runtime I get the following error :

 TlsException: Invalid certificate received from server. Error code: 0xffffffff80092012
 Mono.Security.Protocol.Tls.Handshake.Client.TlsServerCertificate.validateCertificates (Mono.Security.X509.X509CertificateCollection certificates)

Googling the error yield solutions using the ServicePointManager.ServerCertificateValidationCallback method, which I can't use do due to .net Core restrictions.

What is the proper way to validate my certificate for Hololens ?

Curent Settings:

• Unity 5.5.1f1 & HoloToolkit v 1.5.5.0

• Build settings : SDK Universal 10, Target device Hololens, Build Type D3D

• Compilation override : Use Net Core

• On all my DLL's : Checkbox "Don't Process" ticked