通过 demo, 内的 mqtt_demo (1) ; 无法连接服务器.
-----------conn_type 1 ctx 0x20025744 mqtt_demo_socket_id 0x20025748
----------------sta ip: 192. 168. 2. 170
----------------step1: init mqtt lib.
----------------step2: establishing TCP connection.
. Seeding the random number generator. . . ok
. Connecting to tcp. . . ok
. Setting up the SSL/TLS structure. . . ok
. Performing the SSL/TLS handshake. . . ok
----------------step3: establishing mqtt connection.
tls recv -30848 closed
----------------Error (-30848) on read packet!