Calories calculator is not accurate

I take off my vivosamrt HR watch during sleeping and switch it off.. when i turn it on in the morning it shows 450 kcal consumed..
And yesterday i didn't put on the watch all day and it showed 1220 kcal burned..

How can i fix this problem

It's not an issue. Your body consumes energy to "do nothing" :-). https://en.wikipedia.org/wiki/Basal_metabolic_rate