Oppo android auto text apps

I’ve downloaded a few apps (ifttt, trigger, power outage alarm) whose function has been set to send an SMS message when the charger is unplugged (trying to use as a power monitoring alarm for cold stock storage).

I unplug the charger and a message comes up '“appname” would send SMS to “number-i-entered”
Content: “what I told it to send”.

It has a cancel button and a send button. The cancel button has a countdown from 9. After it counts out nothing has sent.

It’s the same with all three apps and I can’t find anywhere online where folks are having the same issue, so maybe it’s the phone having a secret setting. It’s an oppo a73.

Please help!!

If you can’t find why your phone. Possibly use autoinput to push send for you? Or Tasker? Or is Tasker on your list of tried apps?

I know people use Tasker to do things when phone switches from AC charger to battery. Myself included.