Potential Security Risk Ahead Error on non-www urls

My issue is when I open my website without WWW then it doesn’t redirect to https://www.admecindia.co.in, in result page doesn’t open up and shows ‘Security Error’ like this:

Warning: Potential Security Risk Ahead

Firefox detected a potential security threat and did not continue to admecindia.co.in. If you visit this site, attackers could try to steal information like your passwords, emails, or credit card details.

When i click on the Advanced Button given there, then it shows this.

Websites prove their identity via certificates. Firefox does not trust this site because it uses a certificate that is not valid for admecindia.co.in. The certificate is only valid for www.admecindia.co.in.

Error code: SSL_ERROR_BAD_CERT_DOMAIN

my .htaccess code is:

<IfModule mod_rewrite.c>
 RewriteEngine On
  RewriteBase /

  RewriteCond %{HTTP_HOST} ^admecindia\.co\.in$ [NC]
  RewriteRule ^(.*)$ https://www.admecindia.co.in/$1 [L,R=301]
 

  RewriteRule ^index\.php$ - [L]
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule . /index.php [L]

</IfModule>

thanks