Hello. I created 3 sites to GetGrav, and i have a problem - nothing links in google and other search engines. But I have site, that maked on simple html and moved to Grav - and it very well indexing in Google
is your site definitely not listed in google? or, maybe is all about page-rank?. I recommend you register those websites in google webmasters and read what google have to say about your website. remember grav is only the cms, what really matters is your content.
As Hugo says, this is a more general issue on how to make your site visible on search engines, not grav-specific.
If Google can index it (not blocked by robots.txt), then it is on Google.