windows 10 timer notification

The Pomodori Timer notification in the Windows App does not work. When the app is minimized (which it of course is since I'm working), the app does not notify when the timer is finished. That only happens when maximizing the app again. At that time, the timer jumps to 0 and the notification sound is heard that the timer finished a session. For me personally this renders the whole app useless as I work with pomodori timers to focus and was searching for an app that integrates this in my schedule. My trial period ends in 12 days. Would be grat if this is fixed or let me know if I'm overlooking some setting. If this is fixed I would certainly buy the year subscription.