Why can there be a "file_exists(): open_basedir restriction in effect" error?

Question

PHP

Debian+Nginx+PHP-fpm.
In the nginx config I entered:

fastcgi_param PHP_ADMIN_VALUE "open_basedir = /tmp:/var/www/site:/var/www/content";

Went to the site and...

Warning: file_exists(): open_basedir restriction in effect. 
File(/var/www/content/bla-bla/bla.php) is not within the allowed path(s): (/tmp:/var/www/site:/var/www/content)

The config seems to be correct, everything works, but the error is annoying. Is the syntax wrong?

Answer 1

"open_basedir = /var/www/content";? I don't know about NGINX myself

Answer 2

Allowed folders:
And your script is
add this path

Answer 3

In the pool settings, check if basedir is there.
If there is a pool in the settings, then it is used.