too many redirects when using SSL

Question

Im having an issue with https redirects. Ive tested in chrome, firefox and safari.

When i load my website using https i get the errors

Firefox: "The page isn't redirecting properly" Chrome: "ERR_TOO_MANY_REDIRECTS" Safari: "Too many redirects occuring"

Nginx conf

server {
    listen 80;
    return 301 https://$host$request_uri;
}

server {
    listen       443 ssl;
    server_name  example.com;

    ssl on;
    ssl_certificate /etc/nginx/ssl/server.crt;
    ssl_certificate_key /etc/nginx/ssl/server.key; 
    ssl_session_timeout 1d;
    ssl_session_cache shared:SSL:50m;
    ssl_session_tickets off;

    ssl_dhparam /etc/nginx/ssl/dhparam.pem;

    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers 'ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS';
    ssl_prefer_server_ciphers on;

    add_header Strict-Transport-Security max-age=15768000;

#    ssl_stapling on;
#    ssl_stapling_verify on;

    resolver 8.8.8.8;

    #access_log  logs/host.access.log  main;

    location / {
        root   /srv/public;
        index  index.php;
    # example
        #ModSecurityEnabled on;
        #ModSecurityConfig /etc/nginx/modsecurity.conf;
    }

    error_page  404              /404.html;
    location = /404.html {
        root   /usr/share/nginx/html;
    }

    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }

    location ~ \.php$ {
        root           /srv/public;
        fastcgi_pass   unix:/var/run/php-fpm.sock;
        fastcgi_index  index.php;
        fastcgi_param  SCRIPT_FILENAME   $document_root$fastcgi_script_name;
        include        fastcgi_params;
    }

}

I am using a piece of software (whmcs) which has its own built in https redirect.

I'm also using cloudflare (SSL set to Full - not strict).

If i remove the https url from the software (whmcs) I can manually navigate to https://example.com. and it works fine.

Im guessing that the issue may be a combination of cloudflare whmcs and my nginx configuration together but i cant work out whats going wrong.

when i nagivate to https://example.com, i can see in firebug a number of 302 status codes, and in the header it shows location as http://example.com.