I'm not sure if the reminders actually work

What can I do to make sure that caynax actually chimes?

Hi. What device do you use?

Hi! Same worry here. I was using free version and worked properly, but now I bought the pro version and it doesn’t chime at all. My phone is a Xiaomi Poco X3 Pro

If you use Android 12 then I have ongoing issue there as since Android 12 background restrictions application crashes on some devices.