I don't see a notification when an expiration date has passed on my board. I have added a date to my cards, but I'm not receiving a pop-up notification on my smartphones (Samsung, iPhone) or tablet (iPad).
See picture: that card has a due date but I didn't receive a notification. 
It worked before, but now suddenly no longer.
All my other notifications from apps like Facebook LinkedIn Instagram work correctly.
Thx for helping out.