For Android 6+ check app's Permissions, you can find it in device's Settings / Apps / GnomGuru / Permissions
1. Make sure the option
automatically send SMS from this device is ON
2. Check the templates to make sure there are no errors on them (highlighted in red)
3. Verify that the default reminder is set. Reminders are added as default to the event at its creation.
1. Create a Test Appointment (for the future, not for the past)
2. Add a Participant.
3. Make sure that the default reminder is added.
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