Pixhawk4 B/E lamp flashes red


We’ve been preparing for the underwater vehicles festival.We use Pixhawk4 with Q ground control.Unfortunately We observe red flash on Pixhawk 4 B/E lamb when we make the connections of the vehicle with the thrusters and battery.We use joystick while Q Ground Control in Manul mode.
How can we fix that problem,I think this is about a safety problem but when lamb flash we didn’t get any error messages.