Notifications wont work

I have ADHD and severely forget to do things so I need to stay organized for college/life, I like to plan ahead, this isnt functional, and it fails to notify me even when I have it on in settings... Its caused me to forget a TON of important things, like no, Im going to find something more reliable.

Heyymickie about Do! - Simple To Do List, v5.6.0