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collections/_documentation/invoices.md

@@ -322,9 +322,11 @@ Spreadsheet templates are powered by [PhpSpreadsheet](https://github.com/PHPOffi
 **Important:** within the first 100 rows you MUST-HAVE the template row for timesheet entries, which means there must be
 a value starting with `${entry.` in one of the first 10 columns, otherwise no timesheet records will be rendered!
 
+If you don't have that, you will see the error `Invalid invoice document, no template row found.`.
+
 _Check the default templates if that doesn't make sense to you ;-)_
 
-This row will then be cloned for every timesheet entry.
+The row containing the `${entry.` template will be cloned for every timesheet entry.
 
 See below in `Template variables` to find out which variables you can use.