CF-SX3@makoto 12:01:54/201212(~)% foreach i (993 )       
echo $i;  openssl x509 -text -noout -in <(openssl s_client -connect imap4.example.com:$i) |& grep -A3 Validity
end
993
depth=2 O = Digital Signature Trust Co., CN = DST Root CA X3
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = Let's Encrypt Authority X3
verify return:1
depth=0 CN = imap4.example.com
verify error:num=10:certificate has expired
notAfter=Dec 12 00:12:03 2020 GMT
verify return:1
depth=0 CN = imap4.example.com
notAfter=Dec 12 00:12:03 2020 GMT
verify return:1
DONE
        Validity
            Not Before: Sep 13 00:12:03 2020 GMT
            Not After : Dec 12 00:12:03 2020 GMT
        Subject: CN = imap4.example.com

   79  2020-12-12 20:10  sudo certbot-3.8 certonly --webroot  -d imap4.example.com 

webroot path used be on the command line, but not for now, and it asks later at dialog

CF-SX3@makoto 22:51:52/201212(~)% 
openssl x509 -text -noout -in <(openssl s_client -connect imap4.example.com:587 -starttls smtp ) |& grep -A3 Validity

depth=2 O = Digital Signature Trust Co., CN = DST Root CA X3
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = R3
verify return:1
depth=0 CN = imap4.example.com
verify return:1
250 HELP
DONE
        Validity
            Not Before: Dec 12 10:10:56 2020 GMT
            Not After : Mar 12 10:10:56 2021 GMT
        Subject: CN = imap4.example.com
CF-SX3@makoto 22:52:04/201212(~)%

openssl x509 -text -noout -in <(openssl s_client -connect imap4.example.com:587  )
18446744073709551615:error:1408F10B:SSL routines:ssl3_get_record:
wrong version number:/usr/src/crypto/external/bsd/openssl/dist/ssl/record/ssl3_record.c:332:
unable to load certificate
18446744073709551615:error:0909006C:PEM routines:get_name:
no start line:/usr/src/crypto/external/bsd/openssl/dist/crypto/pem/pem_lib.c:745:
Expecting: TRUSTED CERTIFICATE