I have the same problem.
https://search.google.com/test/mobile-friendly?id=AQAN8gUkCZU1Ae0ZfZsGnQ
Can you see what is wrong with my site? I like the theme and have been using it for several years now, but with Google telling us a site needs to be mobile friendly I like to know what I have to change.
Thanks for the help and a great theme.
Edward