Lotus Bud Mindfulness Bell relies on notifications to deliver you mindfulness alerts randomly throughout the day. In order to do this Lotus Bud has to wake up in the background periodically to schedule the next set of notifications.
There is something you might be doing that will prevent Lotus Bud from working properly.
Never swipe Lotus Bud away in the app switching interface!
Don't swipe Lotus Bud away in the app switching interface. Why is this important? Apple includes this feature for one reason only. If an app is misbehaving and won't respond, or keeps crashing on you, this is a tool to help reset some things in the app so you can give it a fresh start and try again. You should NEVER do this to an otherwise well behaved app! It is a troubleshooting feature only. You may have heard from some of your friends or family that you should just do this to every app when you're done using it to save battery. This is a myth that has been spread by well-intended people, but it's simply not true. In fact it can make your battery life worse. Apps on your phone don't behave like apps on a computer, they don't need to be closed to stop them from running. By default if you do not see them they are not running. They can ask for special permission to do some things in the background while you're not using them, but iPhone is in charge of making sure when it's ok to do this.
There are some very smart people that have looked into this and have written an article about it: Closing Apps to Save Your Battery Only Makes Things Worse! Apple has also confirmed that there is no need to force close apps (under normal circumstances).
These special tasks that Lotus Bud does is to schedule the next ten or so mindfulness reminders. When this happens Lotus Bud gets a chance to wake up, schedule a few more bells, and then it goes back to sleep. All of this happens in a fraction of a second and uses almost no battery at all.
So to keep getting your mindfulness reminders don't close Lotus Bud from the app switcher.
For other tips on how to make sure Lotus Bud will work the best see here.