Redirect all www addresses to non-www web addresses
Uncomment lines 93 and 94 in the .htaccess file that comes with Drupal in the web root.

RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
RewiteRule ^ http://%1%{REQUEST_URI} [L,R=301]


EDIT: If the certificate requires https, edit the second line to read:

RewiteRule ^ https://%1%{REQUEST_URI} [L,R=301]