I used to connect my NodeMCU via MQTT back then at January 2021 using said tutorial above and succeed, i don’t know why all of sudden it can’t work anymore. Any help or suggestion is appreciated!
to make sure you’re device is already connected to the Internet:
1. Is my device connected to the Internet?
This can be as simple as putting your SIM card in a phone and checking if it has data coverage. Then, do the same with your device and try to reach the outside world with a corresponding AT command.
2. Can you Publish or Subscribe via MQTT?
To check this, simply publish or subscribe to an external site and make sure your hardware is working correctly.