404 page when no product on sale

Hello, firstly thank you for the plugin.

I’m running into a problem whereby my site is displaying a 404 page if no sale products are found. Ideally, I’d like it to display a message saying: “There are currently no products on sale, please check back later” rather than directing to a 404 page. Is this possible?

The page works fine once a product is marked as ‘for sale’ (has a sale price).

Thank you.

https://wordpress.org/plugins/on-sale-page-for-woocommerce/