Rotary encoder plugin - no button response


I installed the rotary encoder plugin v1.2.2 within Volumio and entered the required gpio pins.
While turning the knob, the volume control I selected in the setting works perfectly using 67nf capacitors, but I can’t get the push-button functionality to work. I tried many different gpio-pins (except gpios 3,5,18,19,20,21 which are used by the hifiberry amp2), but no success. I measured the encoder (KY040), pushing the button connects the sw-pin to the ground-pin, so to me the encoder seems to work properly.

Any help would be very appreciated, thanks in advance,

edit: updated to volumio 2.799, same problem.

Volumio Version: 2.779 + 2.799
Hardware: rpi 3
DAC: hifiberry amp2


Finally got it fixed by adding gpio-directives in the /boot/config.txt


This way I deactivated the internal raspberry pullup-resistors on gpio 4+27, where the CLK and DT pins of the encoder are connected for rotating volome control.

Gpio 22, the switch pin, I configured as input with pullup-resistor.

Works perfectly now.