my wp-admin login not accepting me again.

I am the designer and the admin to a comapany’s site https://www.foreverwealth.org, but each time i access the site backend with the username and password, it suddenly refuse to access, instead it will showing this error: “This action has been prevented for security measures” . The issue is that it does not even open the admin login screen again, instead it shows the site login interface which is meant for user login. I still remember i disabled admin login from guest. And now the site is seeing me as guest because i logged out from wpadmin and then login through the user login page. Then going back to login to wpadmin page again, it does not accept me again and neither does it open the wpadmin login page. It only shows this message “This action has been prevented for security measures”. I dont know what to do. I can’t login to admin to work on the site. Help! I have tried different browser and devices. I have even clered cache in my browser and tried again. No way! Help!