Hi @Stephanie_Rios 
and welcome to the Forum!
Sorry for the confusion here. Browser notifications appear when your teammates assign you a task, comment on a task you’re following, or add you as a collaborator of a task. As it stands, there is no browser notification for tasks that are on due.
There is a popular request in the Forum regarding this topic: Push Notifications at 'Due Time'
In case you haven’t yet, I would recommend you to upvote it!
Please, let me know if there is anything else I can help you with! Have a nice Thursday!