Welcome back to our forum, @acmaj,
Allow me to step in for a moment and share some information to help resolve the errors.
If you're using the Automated Sales Tax feature, QuickBooks calculates taxes for shipping charges based on your state's tax regulations . However, if you're using the Sales Tax Center, you will only see a Shipping charge box which isn't taxable. As a workaround, you can create a taxable service item then apply it to your sales transactions.
You can now use this item on your invoices or sales receipts.
If you'd like to know which states tax shipping costs and which don't, please check out this article: What Small Businesses Need to Know About Sales Tax and Shipping?
Let me know if you have any more questions about the Sales Tax feature in QuickBooks. I'm here to lend you a hand whenever you need one. Have a great day!