The problem was fixed
To solve this problem, change the specified code in the httaccss file as follows
<IfModule mod_rewrite.c>
Options -MultiViews
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule \.(js|css|jpeg|jpg|gif|png|ico|map)(\?|$) /404error.php [L,NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
After the changes
<IfModule mod_rewrite.c>
Options -MultiViews
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule \.(js|css|jpeg|jpg|gif|png|ico|map)(\?|$) /404error.php [L,NC]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ./ /index.php [L]
</IfModule>
Once you modify this rewrite rule, password protection of the internal folder should work as expected. Clear your browser cache and check the changes.