OpenSSL s_client -connect sometimes fails

[tradel]

OpenSSL occasionally fails to handshake with Envoy with the following messages:

RuntimeError: No PEM certificates found in stream:
CONNECTED(00000003)
write:errno=0
---
no peer certificate available
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No client certificate CA names sent
---
SSL handshake has read 0 bytes and written 218 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
No ALPN negotiated
SSL-Session:
    Protocol  : TLSv1.2
    Cipher    : 0000
    Session-ID: 
    Session-ID-ctx: 
    Master-Key: 
    PSK identity: None
    PSK identity hint: None
    SRP username: None
    Start Time: 1551563371
    Timeout   : 7200 (sec)
    Verify return code: 0 (ok)
    Extended master secret: no
---