(please specify the URL of the site on which you are experiencing the problem:
I try to install the SSL certificate but Google Trust make an issue about it)
Error Message : SSL issue
(please share the FULL error message you see, if applicable ) : SSL issue by Google Trust LCC
Please click here How to force all traffic to HTTPS
and read the article that @KangJL linked you (I set it to open the part that mentions the .htaccess file),
then do as it says.