Major of expiration mails don't arrive

Hi, when I started to use letencrypt it sent me mail to alert expiration certificate near all time, recently don't send it on major of cases but I not understand why.
I use lego (GitHub - go-acme/lego: Let's Encrypt/ACME client and library written in Go) for creation and renew using dns validation (using duckdns) as certbot don't permit custom https port (I have on near all server, I can't on standard port because all clients have connection with only one ipv4 and many servers, I can use certbot and standard port only in few webserver in ovh.
I saw something to try reenable send mail expiration with certbot (even if I not disabled them and I don't know if will solves the issue, is there a way to do the same for certificate created without certbot?
is there a way to check if is enabled or not the expiration mail on a certificate?

thanks for any reply and sorry for my bad english