Common Issues & How to Fix Them

Selling Plan Cannot Be Applied to Variant

This error typically occurs when the plan picker does not register that the selected variant has changed. This can occur for a variety of reasons, but the fix is usually the same:
In your theme's Javascript, often there is a function that is called on variant change. If not, create one. Within this function, add the following:
document.querySelector('[name=id]').dispatchEvent(new Event('change'))
This event is listened for within skio-plan-picker.js to call the update method that will apply the correct selling plan to the new variant.
Alternatively, you may try looking through the commented event listeners (found in skio-plan-picker.js, denoted by the comment // LISTENERS. Apply each individually to see if they work for your theme, as the default listener may not.