Hi,
In the module's settings, you have the id 1334 in the menu setting.
This means that when you use the module's filters, it will filter the products displayed by the menu item with the id 1334.
So that menu item has to display all your products by default if you then want the filters to search among them for the results.
So the problem probably comes from the settings of the menu item with the id 1334 which is not configured to display all the products by default. Could you check its settings via the Joomla menu manager ?