Hi there, 1433092075.
I'm here to make sure you'll be able to get rid of this error message when submitting a VAT return in QuickBooks Online (QBO).
Let's turn off the close the books function in the Account and Settings. I'll show you how:
- Go to the Gear icon.
- Select Account and Settings under Your Company.
- Click Advanced.
- Check if there is a date entered under the close the books section. If there is, please removed it and toggle it off.

- Select Save and Done.
Once done, try to submit the VAT return again.
For more tips in preparing and filing your VAT return in QuickBooks Online, you can read these articles:
Stay around if you have any other concerns or follow-up questions about VAT. Have a great rest of the day.