BuddyPress.org

Your current registration page url ends with __trashed, so your link is still pointing to that page.
You can edit links or create custom links by going to …wp-admin > Appearance > Menus

But you cannot just replace the register page, if that is what you did.

Have you read the
modifying-the-registration-form

You can customize the layout by editing the template.
If you are using the Legacy Template pack, this is the file:
buddypress\bp-templates\bp-legacy\buddypress\members\register.php

Instead of editing core files, you can overload a template in your child theme.
Read this.