You don't have permission to access /nagios/ on this server

Hi,
I keep getting “You don’t have permission to access /nagios/ on this server” massage wheny trying to loging with “nagiosadmin” user after fresh installation.
Install 2 times with Fedora and one time with CentOS - Same Problem !!!
I followed thw documentation step by step.
Please help.

which documentation did you follow?
From the errror you have the problem lies most probably in the apache configuration. Check your apache and nagios logs and see if it gives any hints.