Google's mobile friendly test says my site is not mobile friendly
Many website owners may get automated emails from Google Search Console, reporting on mobile usability. You can also manually run a test on your site's mobile usability here.
Occasionally, you may see a result that your site is not mobile friendly. If you know you are running a mobile responsive theme, this can be confusing!
MOST COMMON CAUSE FOR "PAGE IS NOT MOBILE FRIENDLY" RESULT
The test that Google runs is done with bots, not live users/readers. Sometimes, due to settings with your hosting provider, caching plugins, or simply site load time, the testing bots aren't able to load the full version of your site — specifically, the site stylesheet, which is responsible for how the site looks, feels, and is formatted. When this happens, you may see a jumbled, messy version of your site in the Rendered Page screenshot preview on the right of the testing screen. Or, certain elements on your site might not load properly, and don't mirror what you see when you load the site on your mobile device.
If the version of the site you see in the screenshot does NOT match the version of your site you see on mobile, it means that Google has not properly loaded your site, and that's what's causing all the usability issues and errors.
In this case, you can ignore the test results and the "not mobile friendly" result, because it is not an accurate test result. You do not need to do anything; eventually, Google will crawl your site again, and if you checked on another day in the future, you're just as likely to have passed the test with flying colors!
Here is an example of an improperly loaded pages can look in the Mobile-Friendly testing preview:
Notice how this user's website looks stripped down — you can see their site menu links, but they're bulleted, with no formatting. This is because Google's Mobile-Friendly Test has not loaded this site's stylesheet, which would control how these elements look and feel.
If your own site looks similar to this, or has other formatting issues in the preview that you can't reproduce on your own mobile device, it means Google is not properly loading your site stylesheet, and your test result is not accurate!