In your first posting you said the url to login was site/ocen/moodle/ Is there a config.php file in /ocen/ or is there a moodle directory inside ocen and inside the 'moodle' directory there a config.php file?
Think WordPresses have plugins for redirects ... check WP config.
Redirects can be done in multiple ways ... kinda depends upon if one is running Apache/Nginx/IIS on Windows, etct.
So I can do no more other than to point you to Apache Docs .... assuming you are running Apache:
https://httpd.apache.org/docs/2.4/rewrite/remapping.html
nginx
https://www.nginx.com/blog/creating-nginx-rewrite-rules/
rewrites from .htaccess .... the following from a hosting provider that may/may not fit your situation.
In the config of PayPal ... their end ... did you have to enter any 'call back url' that points back to your site?
Ken