The application should be working a lot better on new versions of the app (3.1.0+). If you are receiving no reminders at all, please refer to our troubleshooting guide: https://calendarsnooze.uservoice.com/knowledgebase/articles/1838176-no-reminders-at-all
Thank you for contacting support.
we are working on this bug and i will upload a fixed version as soon as we have found a solution.Steven D Rothkin commented
I just installed fresh on Pixel 3 Android Pie after several years of not using it because it wasn't reliable on Nexus 6 Android 7.1 (I previously emailed you on it). Hope this will be fixed soon.