Auto Update not happening, site looses certification

I have been having some problems with the theme not auto updating lately. And when it doesn’t, my site ends up showing as not secure with a time error. When I bypass the message and update the theme manually the issue is resolved, but this has happened several times in the past month or two and it is not looking very professional. The web host has tried to fix, but so far it has not solved anything.
What am I missing to get this theme to always auto update? Auto update for themes and plugins are set to ‘on’ in wordpress