Plugin triggered when adding a sharepoint document

Hello Folks,

I'm trying to develop a plugin that fires when a sharepoint document is added to a CRM entity.
So for that I developed a plugin that is supposed to be triggered on a post operation creation on the entity SharePoint document that is described in this link: <<here>>https://docs.microsoft.com/en-us/dynamics365/customer-engagement/developer/entities/sharepointdocument

Unfortunately, the plugin does not seem to trigger when I add a document.

Here is the way I have registed the step of the plugin:

And here is the code of the plugin:

namespace CEP.Crm.Plugins
{
    using System;
    using System.ServiceModel;
    using Microsoft.Xrm.Sdk;
    using CEP.Crm.Plugins.Manager;

    /// <summary>
    /// PostSharePointDocumentCreate Plugin.
    /// Fires when the record is created
    /// All Attributes
    /// </summary>
    public class PostSharePointDocumentCreate : Plugin
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="PostAccountUpdate"/> class.
        /// </summary>
        public PostSharePointDocumentCreate()
            : base(typeof(PostSharePointDocumentCreate))
        {
            base.RegisteredEvents.Add(new Tuple<int, string, string, Action<LocalPluginContext>>(40, "create", "sharepointdocument", new Action<LocalPluginContext>(ExecutePostSharePointDocumentCreate)));


        }

                protected void ExecutePostSharePointDocumentCreate(LocalPluginContext localContext)
        {
            if (localContext == null)
            {
                throw new ArgumentNullException("localContext");
            }

            try
            {

                IPluginExecutionContext context = localContext.PluginExecutionContext;
                IOrganizationService orgService = localContext.OrganizationService;
                Entity inputEntity = (context.InputParameters != null && context.InputParameters.Contains("Target")) ? (Entity)context.InputParameters["Target"] : null;
                if (inputEntity == null)
                    return;
                throw new Exception("I'am in the plugin");
            }
            catch (InvalidPluginExecutionException iex)
            {
                throw iex;
            }
        }
    }
}

Does anybody could see why this plugin is not triggered when I had a sharepoint document from the ocument area of a CRM entity (account for example) ?