I used "lol" in my doctoral dissertation, is this why I failed?

I'm a college instructor who is "ABD" or "All but Dissertation." I just need to complete my dissertation in order to become a professor. But I failed, and I was wondering, do you think it's because I often used "lol" in it? You know, "laughing out loud?" The reason I did this was because I made some parts of it to be funny, do you think this wasn't acceptable? Or could it have been something else?