I'm trying to add Self signed certificate on Squirrelmail (serat.16tkja.biz) on localhost, so it would not show NOT SECURED or Red HTTPS with a strikethrough. I have already created the certificate by following the tutorial in this site and import it to browsers (Chrome and Mozzila) but to no avail. The Certificate name is server.crt .
This is the configuration file from my /etc/apache2/sites-available/000-default.conf
<VirtualHost *:80>
    ServerName serat.16tkja.biz
    ServerAlias www.serat.16tkja.biz
    DocumentRoot /usr/share/squirrelmail
    Redirect permanent /usr/share/squirrelmail  https://serat.16tkja.biz </VirtualHost>
this is the default-ssl.conf
<IfModule mod_ssl.c>
    <VirtualHost _default_:443>
            ServerAdmin webmaster@16tkja.biz
            ServerName serat.16tkja.biz
            DocumentRoot /usr/share/squirrelmail
            ErrorLog ${APACHE_LOG_DIR}/error.log
            CustomLog ${APACHE_LOG_DIR}/access.log combined
            SSLEngine on
            SSLCertificateFile      /etc/apache2/ssl/server.crt
            SSLCertificateKeyFile /etc/apache2/ssl/server.key
            #SSLCertificateChainFile /etc/apache2/ssl.crt/server-ca.crt
            #SSLCACertificatePath /etc/ssl/certs/
            #SSLCACertificateFile /etc/apache2/ssl.crt/ca-bundle.crt
            <FilesMatch "\.(cgi|shtml|phtml|php)$">
                            SSLOptions +StdEnvVars
            </FilesMatch>
            <Directory /usr/lib/cgi-bin>
                            SSLOptions +StdEnvVars
            </Directory>
            BrowserMatch "MSIE [2-6]" \
                            nokeepalive ssl-unclean-shutdown \
                            downgrade-1.0 force-response-1.0
            # MSIE 7 and newer should be able to use keepalive
            BrowserMatch "MSIE [17-9]" \  ssl-unclean-shutdown
    </VirtualHost>
this is the /etc/squirrelmail/apache.conf
<VirtualHost *:80>
  DocumentRoot /usr/share/squirrelmail
 ServerName serat.16tkja.biz
 </VirtualHost>
The Certificate installed successfully, and it showed in the browser certificate list. Screenshot of Certificate
 
    