Wow, ok. I've been hit with this issues twice and both times, the Twilio reps failed to let me know about this. I had previously resorted to just turning off any counties. Looks like mu international app users might get functionality back.... if this feature is still live.
Do you happen to know which MaxPrice number would make sense for simple SMS? Figuring it out a reasonable value to use from Twilio's pricing pages is proving quite tricky, because of the amount of dimensions to their pricing.