Issues running Storyline using Firefox

I've published several storyline projects on our LMS (Moodle) for my students.  I've started getting emails that certain buttons and items don't work (for example, I have an entry box where they fill in a number answer to proceed -- many of the students can't see this box and are then stuck as the video won't proceed).  I've investigated the problem (in a Windows environment) and it appears to be browser specific.  That is, when I go in, everything runs great on Internet Explorer and Chrome.  However, when I run Firefox, I get the same issue that my students are reporting.  When I published the story, I did check the HTML5 box.  Any idea how I can either fix this on my end or if I can tell students to change something in their Firefox Browser settings to fix this?  (They can see MOST of the video -- right now, the numeric entry items are the problem.  Although, this is the 2nd day of the class, so who knows if other issues will pop up!).

Janet