wp-admin redirect loop with ssl

I currently have a site running on HTTPS with an SSL plugin activated

Website: https://www.greenwichsentinel.com

SSL Plugin: Really Simple SSL

WordPress Version: 4.0.7 (Multisite)

Everything seem configured correctly, however when trying to log into the site or view any dashboard panel i get caught in a redirect loop.

For example, trying to log in through https://www.greenwichsentinel.com/wp-admin causes the page to go to https://www.greenwichsentinel.com/wp-login.php?redirect_to=http%3A%2F%2Fwww.greenwichsentinel.com%2Fwp-admin%2F&reauth=1 . The only link that seems to work is https://www.greenwichsentinel.com/wp-login.php .

I have checked every setting and cannot see why this issue occurs. Any guidance on this issue is greatly appreciated.

Thank you

Edit 1 Without the plugin activated and with other plugins this is not an issue, it seems to be tied to this specific plugin

you’d be better not using a plugin and editing the .htaccess file (in root of website) something like this at the top:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^somesite.com [NC]
RewriteRule ^(.*)$ https://www.somesite.com/$1 [L,R=301]

so your .htaccess file might look something like this:

RewriteEngine On
RewriteCond %{HTTP_HOST} ^somesite.com [NC]
RewriteRule ^(.*)$ https://www.somesite.com/$1 [L,R=301]

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

and remember to set WordPress Address (URL) and Site Address (URL) in WordPress admin (settings -> general), so that they are on https not http