I had exactly the same symptoms as CS33956 - the black cable connector wasn't fully down in the connector and the glue had gone hard and come off. Pushed the connector home and the expression pedal works again now. Thanks CS33956!
Bit shoddy really - I bought the Pod Go in 2022, roughly a year later one of the black knobs started jittering without being touched. The shop replaced the unit for the one I have now. Roughly one year later the epression pedal cable hung off and the unit was only just over a year old. I think the robustness needs improving especially if it is ment to also be 'giggable'!
Shame really as I really like it and its good value - having said that it should last longer than a year!