I currently connect phone to the phone 1 jack. But both the phone lights are on (phone 1 & 2), is it normal? I don't have anything connect to phone2 jack. Why the light is on?

Today I found out the phone1 light was not on, but the phone2 light was on. The phone didn't work either. I unplugged and re-plugged power back on. Then everything was back to normal. Does anyone have same problem?

Thanks.