[jrowley]

These are relatively new restrictions - have been rolling out since this fall. https://support.twilio.com/hc/en-us/articles/1260800720410-W...

I've found sending from toll free numbers like 1-888 reduced filtering also. Only costs like a dollar or 2 a month extra.

[minerva23]

That's not just anecdotal. The carriers do process short code and toll free traffic differently from regular 10DLC. You don't even need do register an a2p campaign for them.