Shutting down while plugged into power supply

Hi. I just got my iPhone XS Max and whenever I plugged it into power supply it charges for some seconds and the next thing me checking it back it’s at switched off. That means it’s automatically switches off itself.

If I then unplugged the charger it will then power on it self. Then when power on itself I later plug it into power supply and continue using it while charging and no problem but if I just drop the phone down for it to charge it will still power off it self again.