Weird error messages on course review screen

Hi there - This is our first time using Articulate Review - I'm actually on the trial right now trying to determine if it's going to be worth it for us to switch to 360. 

I have two people who want to review the course I've loaded. I sent them a link and they had trouble accessing the review at first but when they finally got into my course they see the attached errors. Each has a different looking error. 

A little later on one of the reviewers was able to get the course to come up using Firefox (originally they were on IE) but the other person still couldn't see it. 

Has anyone encountered this? My clients are primarily corporate users who don't have access to anything but Internet Explorer. Is this going to cause issues? Is there another problem? How do I avoid this happening? It hasn't been a great experience for our first time trying it unfortunately.

Thanks for your help!