I tried applying the conditional formatting add rule server action into this oml file that I received in my other forum post but it keeps showing me the error Object reference not set to an instance of an object not sure where I went wrong when applying this server action but without adding this everything works well. 

The purpose of me adding the conditional formatting action is to check if any cell is empty if it is empty i highlight the cell in red when I download the file I am able to see which cells are not filled up (is planned when I have large datasets easier for user to find). Would greatly appreciate any kind of help!