Did you suddenly get an email from Google Search Console Team today stating that Googlebot cannot access CSS and/or JS files on your website? Don’t panic too much – although you should DEFINITELY feel a bit bad. Google has been asking people to stop blocking their CSS and JS resources from Googlebot for quiet a while now; and they’ve tried their best to help you see what’s being blocked – so if you’re getting this notification today it’s because Google doesn’t know how else to get the point across to you.
So what do you do about this? First off note that this is not a penalty, but a warning that if Google cannot see your whole site you’re rankings may suffer. You can start off with Blocked Resources Report which well … gives you a report of blocked resources.
Additionally most WordPress sites block access to the /wp-includes/ folder by default which would also cause this notification to be generated. Make sure you check your site with the new fetch and render tool so you can see if any necessary resources are being blocked.