[n_o_u]

Just tested via twilio to canadian cell phone and had no issues receiving it.

[dustfinger]

What client region was the twilio data center? What was the exact text sent? Are you comfortable to disclose the make / model of the receiving cell phone as well as its carrier service?

[rsync]

I just tested with twilio as well. I was able to send this string:

"secure communication"

from within the twilio API, via pure SMS (no imessage, etc.) to an iphone SE with a US Mobile (verizon MVNO) sim card.

Was sent from a US number to a US number.

No issues.

[dustfinger]

I added your entry, thank you.