htaccess issue

I’m having a very odd issue with password protected directories. I cannot access my WHMCS admin panel via mobile Safari (page not found) or my affiliate script admin panel, but the very exact links works on desktop within my whitelisted IP. It should prompt for user/pw login external of the whitelisted IP and has always worked before. I found out the WP htaccess rules is the cause, but I don’t know what the workaround is. If I remove the code, my pages in WP all show 404.

This is the htaccess in root WP install:

# BEGIN WordPress
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress

If I comment this section out you, the htaccess will properly prompt for the login details.

The rule is forcing the loading of index.php when I navigate to any URL under my domain.

When you visit https://www.mydomain.com/billing/adminfolder/ from a none white listed IP the .htaccess forces to try and find an index.php instead of loading the password protection file at /home/xxxxxx/.htpasswds/public_html/billing/adminfolder/passwd

This is the one in the admin billing folder:

AuthType Basic
AuthName "SOMEUSER"
AuthUserFile "/home/xxxxxx/.htpasswds/public_html/billing/adminfolder/passwd"
require valid-user
Satisfy Any
order deny,allow
deny from all
Allow from xxx.xxx.xxx.xxx