What do you do when Search Console is detecting mobile usability issues on your site?
When one webmaster took to the Webmaster Help Forum asking for help and noting that the problem is
A) content wider than the screen and B) links too close together
John Mueller gave his expert opinion replying with:
“One of the problems I see here is that we have a really hard time crawling your site -- the server is slow in responding,
which means we can't crawl as much as we'd need to properly understand your website.
In particular, sometimes we can't request the various resources used on your pages, which means we can't reliably confirm that your pages are mobile-friendly.
In general, the ways to improve this include moving to a faster server, reducing the number of resources needed to load your pages, or finding ways to improve the general speed of your pages (eg, using caching, tuning your setup, etc.). “