Does this happen in other browser? Are you viewing the site on a mobile device?
i’m having the issue on my mac and have reports from other readers, i can scroll using my iPhone but I’m got a mobile plug in which helps with a mobile friendly theme.
I don’t suppose you know the CSS code please?
Okay we can try using basic troubleshooting then. Try disabling all plugins and using a bounded theme like 2014/2015 and see if that resolves the issue. If it resolves the issue try re-activating plugins one by one.