The user is apache and finger apache returns
Login: apache Name: Apache
Directory: /var/www Shell: /sbin/nologin
Never logged in.
No mail.
No Plan.
I did:

cd /var/www
cp -R ~/.ssh ./
chown -R apache .ssh
chgrp -R apache .ssh

but apache is still unable to find those keys when calling the php script. I am using an apache virtual host and I copied that same .ssh folder to the DocumentRoot without better results.
Any idea?
Thank you

On the target server you need to create also a ./var/www/.ssh/ directory that should contain the authorized_keys file in which you should add the user "apache" public key.

Instead of copying the root keys or any other key, I would rather create a new set of key with ssh-keygen command under apache user. Transfer the public key to the target server and add that key to the /var/www/.ssh/authorized_keys file.

Thank you for the answer. How do I create a new set of keys with ssh-keygen under he apache user? Do I need to login as apache? I am not sure where to find the password.

Login as root and:
# su apache

$ ssh-keygen -t rsa

Leave the pass phrase empty.