I tried to give it a play, but unfortunately I received the same error another user pointed out below.
I had the same problem with my Mac build that you appear to have. Let me guess, did the export play just fine on your machine? That was the issue with mine. I also used GameMaker. Another crazy thing is that when trying to test HTML for my game on my Mac, it just would not work and I couldn't figure it out for the life of me.
I decided to press on and just make an executable for Mac and Windows. But when I was on the PC, I decided to try out HTML in a test run and it worked just fine and the code hadn't changed at all. I don't know what it is with GMS2 and Mac, if it's the new OS, or something to do with Xcode ... but I feel your pain and I'm sorry more people couldn't give The Business Duck a try.