SSL connection failure to ZNC 1.7.1

gistfile1.txt

[davidp@supernova:~]$ openssl s_client -connect myhostname:myport
CONNECTED(00000003)
write:errno=104
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 0 bytes and written 289 bytes
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : 0000
    Session-ID: 
    Session-ID-ctx: 
    Master-Key: 
    Key-Arg   : None
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1531992929
    Timeout   : 300 (sec)
    Verify return code: 0 (ok)
---

I fixed this by replacing the old znc.pem with a new one generated with znc --makepem. I suspect it was because the key in the old one was only 1024 bits.

It would have been nice if ZNC threw a message on startup that the znc.pem wasn't good enough (assuming that it was ZNC imposing that, and not OpenSSL, that is)