Woocommerce can’t place orders when creating an account at checkout for the first time.

We require customers to create an account at checkout before they can place an order (we sell B2B).
Consequently, a few customers create an account at the checkout stage, and once they’ve filled in their new account details, billing and shipping address etc., then they select their payment method on the checkout page before processing their order.
When they click process order, the little wheel starts turning, however then after 10 seconds or so, a notification pops up saying we can’t process your order, please try again.