Problem when ordering Opencart 1.5.6

The checkout button at the last stage in the cart does not work when trying to order from a mobile phone.

The situation occurs on Opencart 1.5.6, the simple checkout module.

Everything is ok, I checked from different devices, it is not possible to simulate the situation, it arises from customers who have already made orders on our website, while the same customers have an order made from an incognito page on the same device.