If you are using nginx as a webserver you can use this server block. Just replace 127.0.0.1 with your own ip and yourdomain with whatever your domain name is. If you don't have m or www just leave them out. you can try with just server_name _; as second line if you wish as that should work as well:

server {
    listen      172..0.0.1:80 default server;
    server_name yourdomain.com www.yourdomain.com m.yourdomain.com;
    return 301 https://$host$request_uri;
    }

You can add the following to your htaccess file right after the line "# If you must add RewriteRules to change hostname, add them directly below (above all the others)"

#Http to https
#Exclude subdomains
RewriteCond %{HTTP_HOST} ^(www\.)?mydomain.com$ [NC]
RewriteCond %{HTTPS} off
RewriteRule ^ https://www.mydomain.com%{REQUEST_URI} [NC,L,R]
#add www on ssl
RewriteCond %{HTTPS} on
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^ https://www.%{HTTP_HOST}%{REQUEST_URI} [NC,L,R]

what does the below piece of code do?

• mydomain.com   redirect to  https://www.mydomain.com
• www.mydomain.com   redirect to  https://www.mydomain.com
• http://mydomain.com   redirect to  https://www.mydomain.com
• http://www.mydomain.com   redirect to  https://www.mydomain.com
• https://mydomain.com   redirect to  https://www.mydomain.com
• https://www.mydomain.com   does not change anything

This is a tested code and I am using the same code in my server. You can also test it if you want at https://www.campuskarma.in

Thats great help. Many thanks @Rohit Gupta

Sounds like the nasty bug I was chasing here https://github.com/Elgg/Elgg/pull/12143