Plain Text Site After Changing URL

I recently tried to enable Cloudflare SSL and changed the URL in Settings > General from https://www.asquare.edu.hk to https://www.asquare.edu.hk but my site immediately crashed afterwards.

I have tried all solutions suggested in this Change URL Post.

1. I have added a line at the wp-config.php file:

define('WP_HOME','https://asquare.edu.hk/content');
define('WP_SITEURL','https://asquare.edu.hk');

2. Added a line in the function.php file of the only template installed:

update_option('siteurl','https://asquare.edu.hk');
update_option('home','https://asquare.edu.hk/content');

3. I also went into phpMyAdmin and changed both the “siteurl” and “home” strings back to https:// but the site is still displaying as plain text at the moment.

P.S. I have switched the nameservers back to the original hosting company instead of Cloudflare’s just to isolate the problem.

Any advice would be greatly appreciated. Thanks!