IF Formula Query

Hi there,

I have a spreadsheet which using the IF formula should be bringing back either "update Required" or "N/A" depending on if the date in the cell is +21days and greater than today's date. However it is not bringing back the "N/A" false response? $M$1 is ref for TODAY() date. The J column contains either dates, blank cells, or 'TO BE SENT' text.
I hope this makes sense. any help is much appreciated.

The formula is:

=IF($M$1>=(J35+21),"Update Required","N/A")

Cheers in advance :)