500 Internal Server Error with ISPconfig3+NGINX+WordPress+Multisite

Hi,

Getting 500 internal server error when accessed to the site created with ispconfig3+nginx+wordpress+multisite.

The error log says:

" [error] 15209#15209: *1 FastCGI sent in stderr: "PHP message: PHP
Parse error: syntax error, unexpected 'if' (T_IF) in /var/www/clients/client2/web1/web/wp-config.php on line 83" while reading response header from upstream, client: X.Y.Z.A, server: DOMAIN.TLD,
request: "GET / HTTP/1.1", upstream: "fastcgi://unix:/var/lib/php5-fpm/web1.sock:", host: "DOMAIN.TLD" 2015/07/06 17:32:40 [error] 15209#15209: *1 FastCGI sent in stderr: "PHP message: PHP Parse error:
syntax error, unexpected 'if' (T_IF) in /var/www/clients/client2/web1/web/wp-config.php on line 83" while reading response header from upstream, client: X.Y.Z.A, server: DOMAIN.TLD, request:
"GET / HTTP/1.1", upstream: "fastcgi://unix:/var/lib/php5-fpm/web1.sock:", host: "DOMAIN.TLD" 2015/07/06 17:32:42"

And the specific line 83-84 specified in wp-config.php reads like:

if ( !defined('ABSPATH') )
define('ABSPATH', dirname(__FILE__) . '/');

I tried by appending the nginx directives as suggested in https://www.howtoforge.com/community/threads/wordpress-multisite-get-an-502.57031/page-2#post-305120, but no go. Also tried by disabling "fastcgi_intercept_errors on" line in /etc/nginx/sites-available/DOMAIN.TLD.vhost file, the problem persists!

Any clue! Thanks.