How to restore access to ispconfig3?

Question

SSH

When going to ispconfig, it gives an error:

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

Most likely, this situation was caused by the file "/etc/group" (this file was restored manually)
How can I return ispconfig to work?
Any additional information I can provide

Answer 1

Helped:
cd /tmp
wget www.ispconfig.org/downloads/ISPConfig-3-stable.tar.gz
tar xvfz ISPConfig-3-stable.tar.gz
cd ispconfig3_install/install
php -q update.php