Something went wrong: there was an error publishing your course - How to resolve

I heard back from the Articulate Rise techie and he told me it was because my course had an empty attachment block. I learned something new today. I didn't know we couldn't have empty blocks if we want to publish for Review. I had it there as a placeholder to remind the client that I need that document from them. After I removed the empty attachment block, it published! So, I think a few of you should be hired as Articulate techies :-)