You can pull up the Sales Orders for All Customers report to view the last sales order number used. Then, create a new sales order using the next sequential number to get this resolved. Let me guide you how.
Click Customers menu at the top. Then, click Customer Center.
Click the Transactions tab, then click Sales Orders (SO).
Change the Filter by drop-down to All Sales Orders, then Date to All.
Click the Run reports at the bottom. Then, click View as a Report.
Once done, create a new sales order and edit the number to correct the number in your next transaction.
I've attached some screenshots for you.
I've also added our page about income and expenses if you need some help articles for your future tasks.
Please let me know if you have questions. I'll be here to help you some more.
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