SmartThings with with Raspberry Pi 3?

hello everyone, sorry if this is in the wrong forum. I had a fellow reddit user help me with setting this up. I setup mosquitto and configured the files. I’ve add the app and the device handler on smartthings IDE.

I try to connect to the mqtt using my pi’s ip address and port 1883, but I get a connection reset message. I’m not really sure where to go from here. I’d like to have the Pi control the smartthings hub