Thank you reaching out to the Community, @gergoviewines.
I can get this fixed for you in no time. It usually happens when you set your books to close on a specific date in QuickBooks Online.
To file the VAT, I suggest going to the Account and Settings section and make changes. You'll need to untick the box for closing the books.
Here's how:
- Click the Gear icon in the upper-right corner.
- Below Your Company, select Account and Settings.
- Go to the Advanced tab.
- Under Accounting, remove the checkmark on the box beside Close the books.
- Hit Save, then press Done.
Meanwhile, I've attached some articles you can use to close or edit your books in QuickBooks:
Let me know in the comment section below if you have any other questions. Have a great day ahead.