You can log in because you have changed the administrator password to match each system. Your other users cannot log in because they operate using two separate accounts. Your Moodle users will need to change their authentication in their profile to “External Database”, currently they are most likely set to “manual”.
Try editing the user profile and change the authentication method to "External Database", and then ask the user to log in using your Wordpress login credentials. Gotta fix it. If it works, change all other accounts to the same setting. Regards, Lewis
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