WioLTEからSORACOMBeam経由でAzureにデータが送れない

前提・実現したいこと

WioLTEからSORACOMBeamを経由してAzureIoTHubにデータを送りたい
磁気スイッチの変化したというデータを送りたい

発生している問題・エラーメッセージ

### Turn on or reset.
### Connecting to "soracom.io".
### Connecting to MQTT server "beam.soracom.io"
5
### mq ERROR! ###

該当のソースコード

c++
1#include <WioLTEforArduino.h>
2#include <WioLTEClient.h>
3#include <PubSubClient.h>    // https://github.com/SeeedJP/pubsubclient
4#include <stdio.h>
5
6#define MAGNETIC_SWITCE_PIN (WIOLTE_D20)
7
8#define APN               "soracom.io"
9#define USERNAME          "sora"
10#define PASSWORD          "sora"
11
12#define MQTT_SERVER_HOST  "beam.soracom.io"
13#define MQTT_SERVER_PORT  (1883)
14
15#define ID                "wiolte"
16#define OUT_TOPIC         "devices/wiolte/messages/events/"
17#define IN_TOPIC          "devices/wiolte/messages/devicebound/#"
18
19#define INTERVAL          (60000)
20
21WioLTE Wio;
22WioLTEClient WioClient(&Wio);
23PubSubClient MqttClient;
24
25void callback(char* topic, byte* payload, unsigned int length) {
26  SerialUSB.print("Subscribe:");
27  for (int i = 0; i < length; i++) SerialUSB.print((char)payload[i]);
28  SerialUSB.println("");
29}
30
31void setup() {
32  delay(200);
33
34  SerialUSB.println("");
35  SerialUSB.println("--- START ---------------------------------------------------");
36  
37  SerialUSB.println("### I/O Initialize.");
38  Wio.Init();
39  
40  SerialUSB.println("### Power supply ON.");
41  Wio.PowerSupplyLTE(true);
42  delay(500);
43
44  SerialUSB.println("### Turn on or reset.");
45  if (!Wio.TurnOnOrReset()) {
46    SerialUSB.println("### ERROR! ###");
47    return;
48  }
49
50  SerialUSB.println("### Connecting to \""APN"\".");
51  if (!Wio.Activate(APN, USERNAME, PASSWORD)) {
52    SerialUSB.println("### ERROR! ###");
53    return;
54  }
55
56  SerialUSB.println("### Connecting to MQTT server \""MQTT_SERVER_HOST"\"");
57  MqttClient.setServer(MQTT_SERVER_HOST, MQTT_SERVER_PORT);
58  MqttClient.setCallback(callback);
59  MqttClient.setClient(WioClient);
60  if (!MqttClient.connect(ID)) {
61    SerialUSB.println(MqttClient.state());
62    SerialUSB.println("### mq ERROR! ###");
63    return;
64  }
65  MqttClient.subscribe(IN_TOPIC);
66
67  SerialUSB.println("### Setup completed.");
68}
69
70int state=digitalRead(MAGNETIC_SWITCE_PIN);
71int next_state;
72void loop(void) {
73  next_state=digitalRead(MAGNETIC_SWITCE_PIN);
74  if(state != next_state){
75    state = next_state;
76    char data[100];
77    sprintf(data, "%d",state);
78    SerialUSB.println(data);
79    MqttClient.publish(OUT_TOPIC, data);
80  }
81  delay(1000);
82  
83err:
84  unsigned long next = millis();
85  while (millis() < next + INTERVAL)
86  {
87    MqttClient.loop();
88  }
89}