Welcome to the forum!
Most likely, this is the issue. The Shelly doesn’t power up. You may check this by powering the device on your work bench with an old flexible cord attached to pin N and L. You’ll need no lamp for this test! Just check the AP which is set by the device after booting and try to add it to your WLAN! After that, you may install it at the appropriate place - possibly with a bypass.
Thank you very much, it worked perfectly with the neutral wire.
I would like to be able to connect it to the switch button without neutral wire, do you know if it would be possible using the bypass?
Thanks again 
With a 10W lamp it is obligatory to use a bypass if the Shelly Dimmer2 shoe connected without neutral wire! Here’s a diagram:
[Blockierte Grafik: https://smarthome-forum.eu/media/541-ar768-doppeltasterschaltung-ohne-n-png/]
It would be also possible to use a single switch.
Best practice is to include the Shelly WITH neutral wire in your WLAN (on the work bench). After that you may install the device at its intended position with a bypass.
