Scheduled blog posts no longer automatically posting – can you help?

Hi – The last 2 scheduled posts didn’t automatically post. I had to go in and manually publish them. I checked the time zone and everything is OK there. I contacted Bluehost in case my moving to the Cloud had anything to do with it, but they say no. Do you know what else I can do to fix the problem? I won’t know if the next one will work until Thursday and I DON’T WANT TO TEST IT as it will send an email to my subscribers. I just want to know what might be causing it. Thanks.