Again php-fpm and custom php.ini

OK thank you. Now all work fine: I use the hint on https://www.howtoforge.com/tutorial/securing-ispconfig-3-with-a-free-lets-encrypt-ssl-certificate/
to make sym link so on postfix conf so not change at every update.
Then have put in ISPConfig vhost the right point to letsencrypt certificate.
Thanks. The post can be close

 

I add some useful information on letsencrypt certificate:
after all settings I found some error on letsencrypt log and some bad certificate so I login on ISPConfig and on all site, subdomain, subdomain(vhost) etc. I disable letsencrypt certificate and disable ssl.
then go on ssh and update certbot to last version, then revoke all certificate:

Code:

certbot revoke --cert-path /etc/letsencrypt/archive/algoritmica.net-0001/cert1.pem

When certbot ask to delete certificate I say Yes.
This delete all /etc/letsencrypt/archive/algoritmica.net-0001/ folder
I do it on all certificate.

Then I go on ISPConfig site and enable letsencrypt on all site, subdomain etc.

Now all certificate are pretty and work well.