Google has been delivering a consistent message since “mobilegeddon” in 2015: they are switching to mobile-first indexing, and you need to be mobile-first.
Mobile-first means that Google is crawling your mobile site – and is often only looking at your mobile site. Even if your desktop site is the best, if it doesn’t offer an excellent mobile experience, Google will not rank you well.
Google is planning to switch to 100% Mobile-First indexing in 2021, and even now is only cleaning up straggling sites. Google is likely crawling your website mobile-first.
