Why sum of some numbers is 0

Hello,
I am trying to find the sum of some numbers in a column in a maxro book. I make the formula of sum and the sum appears 0. In fakt, althout there are numbers that i am trying to sum not zeros, if i select the number at the end of the sheet on the right side, i see the total that is a value diggerent from 0.
Can you please help me why the sum in a cell apprars 0 and at the end of the sheet it appears the real sum? WhT should i do to calculate the right sum?

Thank you in advance