I think I'll save you a but if unnecessary testing.
Native SMS will soon be deprecated and you will need to move to another messaging option.
You have quite a few options. Only the first will be completely free:
- You can install the HE mobile app and send notifications there
- there is also the built in Pushover option. Great notification app for both IOS and Android.
- HE is adding native Twilio support if you REALLY need your notification to be SMS
- If you are an Android user there is also a 3rd party Join API driver that I wrote. It supports both push and SMS notifications.