by searcing on the forum I fount this related topic closed without a link to a FAQ:
In thoose day I have moved my VPS to a new one and … decide to try to configure the server for use Let’s Encrypt certificate… but if you know how VPS and Dedicated server works… for have a valid SMTP or secure email also for client email you need a valid certificate.
I AM using Comodo Positive SSL who is good for web and also for email … but is very expensive.
Why you let’s encrypt cannot done a certificate like Positive SSL of Comodo that works for secure web and email.
Also email security should be considered. I AM not into web Business so for me is just a stress pay a server… I cannot spend a lot of money also for certificate. Now I have a solution but in the future if the price will gruow UP I will be unable to have my own mail.
Please consider to … implement support for emails… so also Control Panel for VPS and Servers can find solution for let users use mail in secure way easly.
Certificate for email is usefull for be able to send email by SMTP web application, also for receve and configure emails in Thunderbird for example … without use self signed certificate… but I tried to configure Let’s Encrypt also for this but doesn’t work. Only Comodo Positive SSL allow me to protect web side and email side connection.
Hope let’s Encrypt can introduce the support of this because for who has a private server this is a big and important issue: configure email!