ISP Config 3.1 how can install multiple versions of PHP (5.6, 7.1 etc.) in Debian 9

Hello, I installed ISPconfig 3.1 with The Perfect Server - Debian 9 (Stretch) with Apache, BIND, Dovecot, PureFTPD and ISPConfig 3.1 without any problems at my Debian 9.1 Server, but I needs install PHP 5.6 and 7.1.

I locked here and found this tutorial How to install PHP 7.x as PHP-FPM & FastCGI for ISPConfig 3.1 with apt on Debian 8 and 9 and everything looks like ok, and I only install PHP 5.6 and 7.1, because the Perfect server came with PHP 7.0, when I check ISPConfig (srv.example.com:8080), Apache show me error 500.

How can I resolve this?, Can give me any Idea?

Thanks