How do you move a Authorized_keys?

So I have an user that has a private key and public key. These keys work. However I wanted to change the home directory of this user to /var/www/html/example.com/. The reason for it because I want to restrict this user from browsing trough the entire server. here is a YouTube video that I'm following link

By doing some research I found the following:

In principle, moving SSH keys to a root-owned location is easy:

1. Create a suitable root-owned directory, e.g., /etc/ssh/keys, under which authorized keys are stored.
2. Create a subdirectory under this directory for each user, and move each user's authorized_keys file to /etc/ssh/keys/<user>/authorized_keys.
3. Finally, change set AuthorizedKeysFile /etc/ssh/keys/%u/authorized_keys in /etc/ssh/sshd_config.

source

However the responds I get from the server when trying to log in is:
Server refused our key

What could be the cause of this?