base_url on https

I looked again and this is what I actually have at my site in .htaccess:

RewriteCond %{SERVER_PORT} !^443
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
RewriteCond %{REQUEST_URI} !^/\.well-known/acme-challenge/[0-9a-zA-Z_-]+$
RewriteRule (.*) https://mysite.com/$1 [R=301,L]

I'm not sure where lines 2-4 came from or whether they're necessary. mysite.com should be changed to the actual domain.

Also, make sure you're editing the .htaccess file in the MODX root directory (not the core or manager) and not the ht.access file.

Be sure the code comes after these lines:

RewriteEngine On
RewriteBase /

<IfModule mod_rewrite.c>
    Options +FollowSymlinks
  # Options +SymLinksIfOwnerMatch
    RewriteEngine On
   RewriteBase /
</IfModule>



<IfModule mod_rewrite.c>
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [L]
    RewriteCond %{HTTP_HOST} !^www\..+$ [NC]
    RewriteCond %{HTTP_HOST} !=localhost [NC]
    RewriteCond %{HTTP_HOST} !=127.0.0.1
    RewriteRule ^ https://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
</IfModule>

Then I have this:

<IfModule mod_rewrite.c>
    RewriteCond %{SERVER_PORT} !^443
    RewriteRule ^ https://www.domain.co.uk%{REQUEST_URI} [R=301,L]
 </IfModule>

All of that, combined with the server_protocol set to https should definitely force https. If it doesn't, even after manually deleting all the core/cache files, it's time to file a ticket with the host.