Date formula returns 1900-01-00 even when cell is not blank

[Pandion]

So i want column U to automatically fill in the date and time when a value is filled into a cell in column C.
What i dont understand is why it still is returning 1900-01-00 even though the cell in C is not blank. The circular reference formula is working since its working with the exact same formula in/for column V & M, but it doesnt work when the exact same formula is used for the column right next to it, so U & C?

 

[RoryA]

Why are you using circular references, and do you have iterative calculation turned on?

 

[Pandion]

Why are you using circular references, and do you have iterative calculation turned on?

Cause i want it to automatically add formula with the date and time whenever a new row is created.
And yes iterative calculation is turned on.