Cells not updated automatically

I have a formulas that doesnt automatically compute the formula there i
a change in one of the input

There are 3 tabs, A, B,

A is the tab which has the SUMPRODUCT formulas
This formulas reference to data in tab B

Tab B has a column which takes data from Tab C to generate an output
This output will be used by tab A

I realised that if I update the information in tab C, there formulas i
tab A doesnt automatically get updated

I search in the internet and someone mentioned that this could be...

Cells not updated automatically