Payment Freezing – Losing Customers!

Hi, we are using WordPress and Woo Commerce with Paypal for payments at checkout. Payment can be made via Paypal and/or credit/debit card using the iframe. Some customers are reporting the screen freezing and not seeing payment confirmation. Please see example below. Any help would be very much appreciated. Many thanks.

“When ordering on the website the payment did not process as the payment page froze and there was no confirmation of payment. As this was a gift I wanted I even tried a couple of time with one card and again with another but to no avail. I have therefore ordered another gift from a separate supplier”