Why did I get "javax.net.ssl.SSLException: Unexpected end of handshake data" when I connect to Apollo by erlang's ssl module -

i tried connect apollo ssl module follow:

{state, sslsocket} = ssl:connect(hostname, portval, [ {cacertfile, cafile}, {srp_identity, {"admin", "password"}}], infinity) 

cafile pem-encoded ca certificate transformed apollo's keystore.

but got connect result:

tls connection closed 

and exception log in apollo.log

javax.net.ssl.sslexception: unexpected end of handshake data 

my version of erlang 18.0, apollo 1.7.1.

how solve problem? many thanks.