I use Android 6 on Samsung S6. Calender is Business Calender Pro. Reminder is Calender snooze (paid version). Since I got the new version I have the problem that a lot of reminders will not comes up. The result is that I miss a lot of appointments. I have a lot of constantly recurring appointments and single appointments. This problem happens with both types. Every time when I add a new appointment the reminder function works for a short time.