Google Business Profile websites

Google Sites websites and Google Business Profile websites are two separate products. Google Sites is not closing down.

Google Business Profile sites have domains that end with business.site and negocio.site  

Google sent email notifications to owners of Google Business Profiles in early January to let them know of the retirement of the free Google Business Profile website, and then again a final notification in the third week of February. The retirement took place in early March. 

The notifications included links to the relevant article in the GBP help center https://support.google.com/business/answer/14368911 

from where users can access the GBP community if they have additional questions.