Print Button in Display ribbon does not work

Would any know the reason why a Print Button in the Display Ribbon does not work? Sharepoint on line, classic list item

In sharepoint designer, Lists and Libraries, I created a Custom Action - Display Form Ribbon

I choose navigate to URL: javascript:window.print()

Add the image and Ribbon location is within Actions.Controls.....

The Print Icon is on the list item, but it does not respond.