Problem with ssl certificate. The mobile version of the site does not open. How to fix?

Question

Digital certificates

Today the mobile version of the site stopped working.
I go to the normal version everything is in order. I go from the phone a white screen. I tried to go from a PC to the mobile version. Kaspersky swears at the ssl certificate and does not let it go. How to fix the problem?

Answer 1

You have an SSL certificate issued for the "raftlayer.net" domain (and for the "www.raftlayer.net" alias).
And from a mobile phone, it redirects to the "mobile.raftlayer.net" subdomain, to which the certificate does not apply.
When applying for a certificate, you had to specify this subdomain. You need to reissue the certificate (now either a paid certificate or LetsEncrypt using a hosting panel) and add this subdomain to the list, or select a Wildcard certificate. It applies to the domain and all subdomains by default.

Answer 2

As an option - connect SSL via CloudFlare, everything is very easy and free.