Unable to Cast a Matlab COM object in C#

Hello everyone I'm trying to control Matlab from a C# application, so I went for the COM server solution however I can't make it work.

First, I registered my Matlab as COM server using comserver('register','User','all') in the Matlab Command Window. I then referenced this server in my C# project.

After that I implemented simple C# code (the same as what's shown in the documentation) to access a Matlab function that I wrote :

// Create the MATLAB instance 
MLApp.MLApp matlab = new MLApp.MLApp(); // Where the code returns an error
// Change to the directory where the function is located 
matlab.Execute(@"cd C:\Users\jarnoldi\Downloads\");
// Define the output 
object result = null;
// Call the MATLAB function myfunc
matlab.Feval("traj2D_image",1, out result, ParametresBalayage.NomFichier);
// Display result 
object[] res = result as object[];

But I get this error when I try to create the MATLAB instance :

System.InvalidCastException : 'Unable to cast a COM object of type 'System.__ComObject' into interface type 'MLApp.MLApp'. This operation failed, because calling QueryInterface on the COM component for the interface with the IID '{669CEC93-6E22-11CF-A4D6-00A024583C19}' has failed because of the following error : Unspecified error (HRESULT Exception : 0x80004005 (E_FAIL)).'

This is weird because the Matlab instance is created, a new Matlab Command Window opens, but the code doesn't go further and stops.

Does anyone know why I have this problem? Thank you in advance.