What happens when you have prepared, practised, made it sound spontaneous, got the words in the right order, given the audience time to digest it and still you are greeted with stony silence?
Get used to it.
Accept the verdict and move on. You are a speaker, not a comedian. If your story doesn't leave your listeners doubled up in the aisles in fits of hysterics, don't be concerned. Move on to the point that you want to make. The fact that they didn't laugh this time doesn't mean that they won't next time, so carry on regardless.