NodeMCU无法通过TLS连接到Bluemix。

我想尝试将NodeMCU与IBM Bluemix IoT Foundation连接起来。未加密的MQTT连接工作正常，并将数据从BMP180推送到云中。但是，当我开始使用TLS时，它无法连接到代理。我尝试使用mqtt.fx建立TLS连接，它工作正常，看起来NodeMCU是问题所在。 如果我运行以下代码：

orgID="****"
BROKER = orgID..".<bluemix>"
BRPORT = 8883

CLIENTID = "d:"..orgID..":generic_esp:generic_esp_01"
print("ClientID: "..CLIENTID)
BRPWD  = "***********"

BRUSER = "use-token-auth"

local function publish()
   dofile('sensor.lc')
   m:publish('iot-2/evt/esp8266/fmt/json',payload,1,0,
            function(conn) print('Payload published') end)
end

m = mqtt.Client(CLIENTID, 120, BRUSER, BRPWD)
c = false

print('MQTT Init')
m:on('offline', function(con) print('mqtt offline'); c = false end)
m:connect(BROKER, BRPORT, 1, function(conn)
   print('MQTT connected: '..BROKER..':'..BRPORT)
   c = true
   publish()
end)

tmr.alarm(1, 1000, 1, function()
    if not c then
      print('MQTT reconnecting')
      m:close()
      c = false
      m:connect(BROKER, BRPORT, 1, function(conn) print('.. MQTT reconnected: '..BROKER..':'..BRPORT); c = true end)
    end
    if c then
      publish()
    end
 end)

esp8266只会打印“MQTT reconnecting”而无法连接。我的代码有问题还是NodeMCU 1.4中TLS的支持还不完整？