Varnish issue

Hi all, i have one server to host my personal websites and after i installed centos 6.7 and cwp i tryed to activate this option.
 
Apache & Varnish Cache (Varnish on port 80 and apache on port 8181) and is not working i have this error.

Error 503 Service Unavailable

Service Unavailable
Guru Meditation:

XID: 501464563

Varnish cache server

In old versions worked very fine.
I don't have activated csf, mod_security or other features.
Is just clean install.

you need to check if apache is working on your server, if apache works then you would need to check logs and configuration.
Also apache vhosts rebuild could help