"it turns out messages from 5 digit shortcodes often aren't supported over wifi calling." This does not seems plausible. I live in urban area but do not have g

"it turns out messages from 5 digit shortcodes often aren't supported over wifi calling." This does not seems plausible. I live in urban area but do not have good cellural connection at home and my mobile phones are usually route calls via home Wifi. All SMS come through. It is just a low-lever transport and I doubt it cares about message size or numbers.