Set SSH Autenthication in Action/Operation details

[newbie70]

I created a new action to automatically restart the named daemon on a DNS server (Alma Linux) when it is no longer running. Everything works if I put the password as authentication method, but if I want to put SSH it doesn't work.
I created the SSH keys on the Zabbix server (I use appliance) with the ssh-keygen command, I copied the public key on the DNS server with the ssh-copy-id command, no errors reported. If I try to connect from the Zabbix server to the DNS server using ssh root @ DNSServer it works.
The error on zabbix server frontend is "Cannot access public key file /root/.ssh/id_rsa.pub".

I don't understand if the problem is the public kI don't understand if the problem is the public key on the Zabbix server or on the DNS server. What permissions should I assign?
The permissions on the public key are 644 on the zabbix server and 600 on the DNS server

[cyber]

As long as I see... Your zabbix server (user zabbix) cannot see the public key file on that same server in /root/.sshd directory...permissions on file itself can be 644, but what are they for all the directories in path?
Accessing anything as root is a bad idea from security perspective .....