1 Uncommon Cause of Unknown SSL Protocol Errors in cURL
I came across this error just the other day. cURL throws the following error when I was trying to connect to an https host:
Unknown SSL protocol error in connection to <hostname>:-9846
Connecting to the same host using openssl's s_client, the following error was thrown:
error:1408F119:SSL routines:SSL3_GET_RECORD:decryption failed or bad record mac
Turns out, the server my client was trying to connect to was so old, it didn't support TLS! The workaround for this was to force an ssl3 connection.