Shoppers see "We can't process this order right now. Please contact the store owner." What does it mean?

Your store has reached the number of orders your plan allows. Checkout then refuses new orders and shows this message (with your email if available) instead of placing them.

Check it on Orders → Manage Orders: the bar at the top shows how many orders you have used out of your plan's limit, with an Upgrade link. Upgrade your plan from the Subscription page to start taking orders again.

Test orders placed with Place Test Order do not count towards this limit.