Sandbox – SEO WIKI
The sandbox is a filter that Google puts on young and new sites. Sites in the .ru domain zone do not fall under the action of this filter and almost immediately participate in the ranking.
How to determine the imposition of this filter on a resource? If the site’s pages are in the Google cache, but are not displayed, and if the site is not in the first place by the domain name, then the resource is under this filter.
The reason for imposing such sanctions may be a rapid increase in backlinks. The filter is temporary and usually sites are in the sandbox from one month to six months.
To get out of the filter, you should pay attention to the quantity, and most importantly the quality of the links leading to the resource. The better and more thematic external links are, the less chance there is to get under the filter and more likely to get out of it if the Google search engine imposes it.