Need Help: SMS Deliverability Issues (30007 Errors) on DBR Campaign

Hey

or anyone:) — looking for some advice from anyone experienced with DBR / SMS deliverability 👇

I was running a database reactivation campaign for reviews and was sending about ~50 texts/day with nifty image photo in it through a sub-account that’s A2P approved under my EIN. That account ended up getting flagged for too many undeliverable messages.

In hindsight, I think part of the issue was the contact list — it likely had landlines/invalid numbers. I’ve since cleaned the list using ClearoutPhone.io and removed anything that’s not a mobile number.

After that, I moved the campaign to a different sub-account (also A2P verified under a different EIN) and slowed things way down — only sent ~10 messages over 3 hours using a drip.

Still, about half of them came back with carrier error 30007 (blocked/undeliverable), while the other half delivered fine. *I also created a split branch and sent four variations of the message so that the message sequence doesn't sound repetitive.*

Trying to figure out what’s actually causing this: