Your documentation on this page is incorrect:
https://www.akeeba.com/documentation/troubleshooter/atwafissues.html
Using FTP to regain access to your site's administratorThe failsafe way to regain access to your site's administrator backend is using an FTP application or your hosting control panel's File Manager to rename a file.
Go inside the
plugins/system/admintools/admintoolsdirectory on your site (on older versions of Admin Tools:plugins/system/admintools). You will see a file namedmain.php. Rename it tomain-disable.php. This will turn disable the Web Application Firewall from executing and you can access your site's back-end again.After you have fixed the cause of your issue remember to rename
main-disable.phpback tomain.php, otherwise your site will remain unprotected!
No such directory exists (plugins/system/admintools/admintools) and there is no "main.php" file anywhere to be found. HELP! (and please update your documentation...I've encountered this multiple times with various websites I manage.
Thanks
Kara