Can't access apache error logs
Solution 1:
You need to add your username to the group adm
sudo usermod -aG adm YourUserName
You can then access the logfiles as normal user without sudo.
Solution 2:
Try:
sudo cat /var/log/apache2/error.log
Solution 3:
You can log in as root user:
sudo su
And then you are able to do:
cd apache2