Dell Active Pen PN5122W can't connect it

I have Dell Active Pen PN5122W , a Latitude 5320 2-1. I want to connect my new pen to the Dell Display and Peripheral Manager.

The pen is recognized by my laptop, I can write with it in OneNote and the button for erasing and selecting works in OneNote.

But the Dell Display and Peripheral Manager doesn't recognize the pen, and I can't connect it to bluetooth. The app says tip with the point of the pen on the screen and then press and hold the top button (I don't know wchich is the top button, but have tried both) But nothing happens. In Bleutooth the pen is not visible and I can't connect.

Because I can't connect, I can't change the settings for the buttons.