CD4026BE Clock not working
You need a pull down resistor on you clock input if your switch is used to pull the clock input high as it is in the schematic.

The data sheet indicates that the counter is advanced on the positive going edge of the clock input.

The data sheet also indicates that the clock inhibit can be used for negative edge counting as you have experienced.

It would also be a good idea to add a small capacitor across the switch to debounce the switch.