PHP-FPM: ERROR: [pool [name1]] unable to set listen address as it’s already used in another pool ‘[name2]’

This error is telling you that you forgot to update your listening address. You likely have another pool configuration pointing to the same address.

For example, name1.conf is pointing to:

listen = 127.0.0.1:9000

And, name2.conf is pointing to:

listen = 127.0.0.1:9000

Simply update the port on one of the configurations and restart PHP-FPM. For instance, name2.conf could listen on:

listen = 127.0.0.1:9001

Restart:

systemctl restart php7.2-fpm.service