FastCGI: comm with server ... aborted: idle timeout (30 sec)
In the Apache vhost config, try to add the -idle-timeout parameter:
FastCgiExternalServer /var/www/uzivatel/www.domena.xy.php5-fcgi-idle-timeout 60-socket /tmp/php-fpm/php-www.domena.xy.socket -pass-header Authorization
See the documentation for further details.