Printing in Storyline 3 - mobile printing black screen

I have published a course in Storyline 3. (published to LMS as HTML5/flash fallback). I have a print button on a slide that I want the learner to be able to print. I have found useful code here that allows to print in html5:
https://www.elearningfreak.com/storyline/how-to-print-slides-in-articulate-storyline-360-in-html5/

HOWEVER - When printing from the iPad (in both Safari and Chrome) it is printing a black screen with a "please rotate your device" notification. I am attaching a screen grab here for reference. (and Yes, the settings have been set to allow for both portrait and landscape views on mobile output.)