If you see similar errors as below when using openssl to test a https site, it is most likely caused by the SNI that is configured in the reverse proxy or server, like Nginx.
openssl s_client -connect bla.bla.com:443
CONNECTED(00000003)
51089:error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol:/BuildRoot/Library/Caches/com.apple.xbs/Sources/OpenSSL098/OpenSSL098-59.60.1/src/ssl/s23_clnt.c:618:
To make it work, you need to specify the hostname in the command, like this:
openssl s_client -connect bla.bla.com:443 -servername bla.bla.com
References: http://nginx.org/en/docs/http/configuring_https_servers.html#sni
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