DATEADD Function works for some cells, but not others?

[Shelley]

I am trying to use the DATEADD function. Ideally, I'd like to add 12 months, and subtract one day, so if anyone can help me with the formula for this, I'd really appreciate it.

For now, let's consider the formula MOU_EndDate = DATEADD(Analytics[MOU_Date],12,MONTH). Why does this work for some cells and not others (blanks) as shown? Both columns are set to Date format. ANy help is greatly appreciated. Thanks!

[Thiyagu]

I think dateadd works only if there is a date in a date table. Try below

 Column = datecheck[Column1]+365..

[Shelley · Accepted solution]

I don't know why this wasn't working, but I figured out another way to do what I wanted: MOU_EndDate = EOMONTH(Analytics[MOU_Date],11) - and it works for all cells.