Why is process of my add-on beeing killed?

Hello,
I have custom add-on which is essentially python forever loop. It runs fine outside hass.io but after day running as add-on the process is killed.

.`/run.sh: line 19: 57 Killed python3 main.py ${ELAN_URL} ${MQTT_SERVER} -elan-user ${USERNAME} -elan-password ${PASSWORD} -log-level ${LOGLEVEL}

Where can I trace why the process is killed?
Is there any watchdog or something which needs to feeded with keep alive?