Orders remain as payment pending

The whole process is correct, it has many paid applications. I recommend using the full iframe because the window stays short and is not modal, so it looks ugly.

The biggest problem is, following the indications on their platform, when the transaction is OK they recommend you to put a notification URL, and although I have checked it 3 times, and still the payment is still as pending.

I’ve tried to modify the pending payment via a function, but no luck so far either. The documentation should explain a bit more extensively about this issue and how to fix it with WooCommerce.