HTTPS Force Redirect not working in Wordpress

Change the order of the rules. First redirect to https and then let WP take over all of your requests.

<IfModule mod_rewrite.c>
RewriteEngine On

RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

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