BCF-SX2@makoto 16:00:55/191013(~)% openssl s_client -crlf -connect imap4.example.com:993

CONNECTED(00000005)
18446744073709551615:error:1408F10B:SSL routines:ssl3_get_record:
wrong version number:/usr/src/crypto/external/bsd/openssl/dist/ssl/record/ssl3_record.c:332:
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 5 bytes and written 313 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)
---

openssl s_client -tls1 -connect imap4.example.com:993

CONNECTED(00000005)
18446744073709551615:error:1408F10B:SSL routines:ssl3_get_record:
wrong version number:/usr/src/crypto/external/bsd/openssl/dist/ssl/record/ssl3_record.c:332:
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 5 bytes and written 124 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
SSL-Session:
    Protocol  : TLSv1
    Cipher    : 0000
    Session-ID: 
    Session-ID-ctx: 
    Master-Key: 
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1571036057
    Timeout   : 7200 (sec)
    Verify return code: 0 (ok)
    Extended master secret: no
---

tls_cert_file: /usr/pkg/etc/letsencrypt/live/imap4.example.com/fullchain.pem
tls_ca_file:   /usr/pkg/etc/letsencrypt/live/imap4.example.com/fullchain.pem
tls_key_file:  /usr/pkg/etc/letsencrypt/live/imap4.example.com/full+priv.pem

imap4# cd /usr/pkg/etc/letsencrypt/live/imap4.example.com
       cat fullchain.pem privkey.pem > full+priv.pem
imap4# wc *pem
      31      33    1903 cert.pem
      27      29    1647 chain.pem
      86      94    5254 full+priv.pem
      58      62    3550 fullchain.pem
      28      32    1704 privkey.pem
     230     250   14058 total

Now I'm getting the last line as:

* OK [CAPABILITY IMAP4rev1 LITERAL+ ID ENABLE AUTH=LOGIN AUTH=PLAIN SASL-IR] imap4 Cyrus IMAP v2.4.16 server ready

imap4@root 16:46:02/191014(..pkg/etc)% pkg_info |grep cyrus
cyrus-sasl-2.1.25   Simple Authentication and Security Layer
cyrus-imapd-2.4.16nb1 Cyrus IMAP server
cyrus-saslauthd-2.1.25 Cyrus SASL plaintext authentication daemon