[rsync]

Only true mobile phone numbers can receive SMS from shortcodes.

Here is a list of carriers that are properly registered to receive SMS from shortcodes:

https://usshortcodedirectory.com/faq/what-wireless-carriers-...

"... short code carriers have arrangements to exchange messages with mobile phone numbers only ..."[1]

[1] https://support.twilio.com/hc/en-us/articles/223133447-Not-R...

[_-___________-_]

I guess this is a US thing, then. It's definitely not true in general, as I said.