Simple Guide: Using Lets Encrypt SSL certs with Dovecot

Server
21

Yes. Problem was that I'am using serts only in local_name sections
local_name mail.example.com {
ssl_cert = </etc/letsencrypt/live/example.com/fullchain.pem
ssl_key = </etc/letsencrypt/live/example.com/privkey.pem
}

I am using multi domain mail server with one IP.
Refer to Wiki has been closed
With client TLS SNI (Server Name Indication) support

!!!!but dovecot also need default sert&key.!!!
so I just repeat this 2 line at in the start of config.

#
# SSL settings
#

# SSL/TLS support: yes, no, required. <doc/wiki/SSL.txt>
ssl = yes
ssl_cert  = </etc/letsencrypt/live/example.com/fullchain.pem
ssl_key = </etc/letsencrypt/live/example.com/privkey.pem

# PEM encoded X.509 SSL/TLS certificate and private key. They're opened before
# dropping root privileges, so keep the key file unreadable by anyone but
# root. Included doc/mkcert.sh can be used to easily generate self-signed
# certificate, just make sure to update the domains in dovecot-openssl.cnf

local_name mail.example.com {
  ssl_cert  = </etc/letsencrypt/live/example.com/fullchain.pem
  ssl_key = </etc/letsencrypt/live/example.com/privkey.pem
}

Maybe somebody help this