esp8266连接阿里云

我一直连不上MQTT，串口打印输出：
WiFi does not connect, try again ...
Wifi is connected.
IP address:
192.168.31.160
nan
nan
Connecting to MQTT Server ...
MQTT connect failed, error code:255
Connecting to MQTT Server ...
MQTT connect failed, error code:255
Connecting to MQTT Server ...
MQTT connect failed, error code:255
Connecting to MQTT Server ...
MQTT connect failed, error code:255
Connecting to MQTT Server ...
但是，我在别的电脑上可以连上，自己电脑就像上面一样，连不上。。。