SMS & Compliance
Why Business SMS Messages Get Blocked (and How to Fix It)
Business texts get filtered for unregistered A2P traffic, spam-like content, link shorteners, missing opt-out language, and volume spikes. Here's a diagnostic checklist and the fixes.
Quick Answers
Why are my business text messages not being delivered?
The most common causes: your traffic isn't registered under A2P 10DLC, your content trips spam filters (public link shorteners, ALL CAPS, spammy phrasing), you're missing opt-out language, you're texting people who never opted in, or you spiked volume suddenly. Carriers usually filter silently — the message shows 'sent' but never arrives.
How do I know if my SMS is being filtered?
Check delivery receipts in your provider's logs: Twilio error 30007 ('message filtered') is the explicit signal. A delivered/sent ratio dropping below ~95%, or recipients on one carrier not receiving while others do, also indicates filtering.
The main reasons carriers block business SMS
- •Unregistered A2P traffic: sending automated texts on a number with no approved 10DLC campaign.
- •Content triggers: public URL shorteners (bit.ly), excessive capitalization, dollar-sign-heavy promises, phishing-like phrasing.
- •Missing consent: recipients who never opted in report messages as spam, which poisons the sending number's reputation.
- •No opt-out: marketing texts without 'Reply STOP to opt out' violate carrier rules and CTIA guidelines.
- •Volume anomalies: a new number blasting hundreds of messages on day one looks exactly like a spammer.
- •Segment mismatches: content wildly different from what the registered campaign declared.
The fix checklist
- •Register brand + campaign under A2P 10DLC before scaling volume.
- •Use your own branded domain for links instead of public shorteners.
- •Include your business name in the message and STOP language in marketing.
- •Only text contacts with documented opt-in; honor STOP instantly.
- •Warm up new numbers gradually and keep content close to the registered samples.