Apache problem - pages cannot be displayed

[becks87]

Dear for Everyone,

I have a problem which have to be fixed ASAP but i have no idea what to do. This morning i found that all of the web pages hosted on our server cannot be displayed. The ISPConfig control panel works correctly (and fast) and all the other services (mail, mysql, ftp...) works correctly and fastly. First i tried an apache restart, it worked without errors and ISPConfig shows all services working again, and the server is not busy, just between 0.05 and 0.4 in many times. I had make a look on apache log files but haven't found any interesting yet. What can i do? Does anyone have idea?
Thanks!