Based on our requirement, we have to collect bulk data from sensor and send to it as well. So, I have created 2 thread: 1st for data collection and 2nd for data transmission. It worked fine for few hours. after that, one of the thread got freeze and that freeze thread is not running again until it restart the photon board. While transmitting, I have use Photon MQTT lib. In MQTT lib, i have extend the packer size to 7284 per second minimum.