Throttle learning not possible

Hello,
I was just about to calibrate the throttle body on a Passat B5 ANA after cleaning it. The conditions were met, but the start button next to the measurement block is grayed out (image).
The search has not yielded any results so far.
Does anyone have any idea what might be causing this?

Best regards.

Hello,
Following this guide, I had already worked, or rather, attempted to work, because things work differently for me.
It's the case that the adaptation starts without any further confirmation, which deviates from the instructions and initially confused me, especially since it happened quite quickly and I didn't notice it at first.


In the video here, I've captured it, hopefully it will be helpful to someone.



Best regards.

Thank you for your feedback!