why i have this certifica error? maybe becasue of google advetisment?
as long as you changed the ow_includes/config.php url to https and you have a valid certificate added to your domain then it should work.
https://www.ssllabs.com/ssltest/
then do a google search for ssl checker, i dont know what kind of cert you have from what vendor but in the google results you should see a ssl checker that will check your cert and let you know.