Question HoloLens 1: Gestures not recognized in Unity 2019.4 with MRTK 2.8.3

I own an HoloLens 1 and so far I have developed some AR projects with Unity 2018.4.23f1 using the HoloToolkit (the version available in 2018). Now I want to develop a new project for HoloLens 1 with Unity 2019.440f1 LTS and use MRTK 2.8. I also use Visual Studio 2017.
I created a new project and followed Microsoft's instructions on how to install and configure MRTK 2.8.3 (for example, I followed Microsoft manual "Set up a mixed reality project in Unity with the Mixed Reality Toolkit"). I added the MixedRealityToolkit to the new scene I created. For the MRTK Profile configuration, I selected the DefaultHololens1ConfigurationProfile. In the Input section, I activated the InputSystem and selected the DefaultHoloLens1InputSystemProfile.
To verify that everything was correctly configured, I added to the scene a 3D cube, and, following Microsoft suggestions, I added the ObjectManipulator and NearInteractionGrabbable components to the cube. When I connect the HoloLens 1 to Unity through Holographic, I correctly see in the Hololens 1 the cube in the scene. Also, if I move the pointer over the cube, it correctly detects the presence of the cube. However, no gestures are recognized and therefore I cannot have any type of interaction with the cube. Even adding a bounding box with handles doesn't change the situation. The handles are recognized (their icons change) by the pointer, but then gestures are not identified and the presence of my hands in the FOV is not detected.
I tried creating a new project several times starting from scratch, changing profiles and configurations, but the result is always the same. Is there something I'm doing wrong or missing?
thank you for your help