we have a issue with the checkout it gives a error message, however the order is normally in the WC order part but the page after checkout does not jump to the thank you page.
Could you please check how it works with some default WordPress themes like TwentyTwenty or WooCommerce Storefront to understand is it our theme issue or not?
In this case, you need to contact the WooCommerce support team for further solutions because as you see on the default theme the same issue so it’s not something caused by our theme.
I’d be happy to assist if you have any other questions or concerns.