Check if Date is in the past & if a cell is blank

I am trying get excel to show the word "Error" if the date in cell M2 is in the past AND if column L2 is blank however this is not working, any help is much appreciated!

It would be even better if I could get it to see if the date IS today or before today, rather than just before today

=IF(AND(M2<TODAY(),L2=""),"ERROR","OK")