Log troubleshooting

I had a customers website go down this evening.  They said the page they had been presented with was a white page with something about maintenance.  I have tried looking through numerous logs /var/log/ and in the website logs and I am not seeing any issues during that timeframe.  I know the possibility could be a customer issue but curious if anyone knows about a maintenance page, maybe if cwp auto updates something, or if there is a specific log that will tell me something.

What webserver are you using..?!

There are some possibilities.
Check search.

Found something like that:
http://forum.centos-webpanel.com/centos-webpanel-bugs/default-page-changed-to-index-html-on-all-sites!/

Regards,
Netino

I am running Nginx & Varnish & Apache with the specific website set to nginx > apache > php-cgi under webservers domain configuration.

I dont think anyone should have to go in and make settings in every htaccess to fix a cwp issue, that is just not very professional at all.  The outage only seemed to be for about 5 minutes and was back up, so it almost seems to me some kind of update happened that caused it.  does anything in cwp auto update and can it be turned off.