Unable to access the server Nagios.

I can’t access the server of my Nagios. I installed it without any problems, however when I open I get a “Forbidden” error. I got a screen shot of the error report. I hope someone can provide a solution.
Thank you for your help.

Forbidden
You don't have permission to access /nagios3/docs/ on this server.
Apache/2.2.16 (Debain) Server at 192.168.69.6 Port 80
