Force http connection for user in multisite

Hello Good Day ,
I have wordpress network and one ssl certificate I just use ssl for my main domain administration
but my all user can connect https://*.site.com (wildcard) and get a error for unsecured ssl certificate
is not problem but google indexed some user page in https and visitors get a error and not enter to user website
I disable ssl for subdomain but main and subdomain directory the same and error stil work ,
How to I redirect subdomain for https conection to http
in wordpress , Sorry for very bad english