In November I had the same problem. The first tech support person got it "working" but that "fix" only lasted till the next day. The second tech support person got it working and it has worked for about 2 months now. I've re-done what she did and it still acts erratically. It will send a scheduled texts sometimes and not others. It doesn't matter if the text is 50 characters or 500 characters long. It is just indiscriminate about it.

I've updated the app. I've force stop-ed it. I've disabled it. I've uninstalled and re-installed it.  I've rebooted it in between each step and waited to see if it really FIXED it before moving on to the next possibility. So far,nothing has been a permanent fix. I can get it to work randomly at best and that is useless to me. This is a feature I use every day so this is very annoying.

There is also more than one way to schedule a message. I've tried them too. It makes no difference.

Nothing on my phone has changed. Not even new apps.

Thank you so much for responding!