An order can be listed as open for the following reasons:
Any order that has not been paid out will be listed as OPEN. Tapping Save in the Register app will save the order, listing it as OPEN in the Orders app.
Tapping the Clear Order button in the Register app will clear the order, listing it as OPEN in the Orders app.
Any order created from the Tables app  that has yet to be paid will appear as OPEN. While guests are sitting at the table and have yet to pay, the order will appear as OPEN.
If you have a printed receipt showing that the order was paid for, but the order looks like it’s still OPEN instead of PAID or PARTIALLY PAID on your Clover device and from the Web Dashboard, please contact Clover Support to help you adjust transactions after the fact. You can find your Clover Support phone number by logging into your Web dashboard and finding your Clover support phone number in the Support box.Please have the following ready:
Your Merchant ID Number: To verify your identity, you will be asked to provide your Merchant ID Number.
Physical receipts: These can be faxed or emailed when necessary.
Reference Site: https://help.clover.com/faq/why-is-an-order-listed-as-open/