Calc won't sort by date properly

After years of using Calc it now won’t sort by date properly. I normally import a bank statement as a CSV, save as an .xsls file and then sort by date. Now it won’t do it.

When opening your CSV file, in the Text Import dialog box, ensure you have the option “Detect special numbers” checked and/or set the column type of the date columns to the type of date that is in the CSV, and that you have set the language correctly. It also helps to have your LibreOffice language settings set appropriately (Tools \ Options \ Language Settings \ Languages); if you don’t, you may also need to set the date format of the date columns to your date language after the import.

I don’t understand why oit was doing it right before but not now, as I didn’t make any changes to LO myself.

The “detect special numbers” option did it. Thanks.

Thanks for reporting back, dadashton. Please mark my answer as correct, then, thanks.