Here are the 3 possible reasons payments fail when using our Shopify plugin:
The secret API keys entered are incorrect (or you may be using test keys).
The currency of your Shopify store is not in PHP. Your store must be set in PHP to use PayMongo on Shopify.
The amount of the cart is below PHP 100.
Otherwise, our Shopify plugin should be working smoothly.
If you still cannot identify the reason after checking those 3 reasons, please don't hesitate to reach out to us via [email protected].