Outbound calls tagged as 'Spam likely'

Last updated: July 11, 2025

1. Why are my outbound calls blocked or marked as “Spam Likely” or “Scam Likely”?
Carriers and analytics partners (like Hiya, First Orion, and TNS) constantly score incoming calls for spam risk. If your number shows calling patterns that look like spoofing or high‑volume bursts, they’ll add a nuisance label or block the caller ID outright to protect their subscribers.

2. How can I remove a spam or nuisance label from my Twilio/Synthflow number?
– Register your US numbers with the FCC’s free Caller Registration service.
– Register with each major analytics partner:

– Update CNAM (Caller ID Name) so your brand shows instead of “Unknown.” This boosts answer rates once the label is registered.

3. What is CNAM, and how do I update it?
CNAM is the “Caller ID Name” delivered alongside your number. A clear business name builds trust. Twilio’s CNAM feature lets you set or remove the name linked to a US number. After purchasing the number via your Twilio account, submit your desired CNAM through the Twilio Console under “Phone Numbers” → your number → “Caller ID Name”.

4. What ongoing best practices keep my caller reputation healthy?
- Keep call volumes steady--no sudden spikes.
- Space out short, high‑frequency bursts.
- Use dedicated numbers per region or team (avoid dozens of agents with different use cases sharing one number).
- Stay TCPA (Telecom Authority)compliant, honor opt‑outs, and follow relevant telecom regulations.

5. How long till registration changes take effect?
Propagation varies by carrier--typically 24 hours to a few days, but sometimes up to three weeks. Patience plus consistent calling behavior is key.

8. Can I register international numbers, too?
Twilio currently supports CNAM updates only in the US. For international numbers, you’ll need to work directly with each country’s carriers or analytics providers. Hiya covers 40+ markets--check their console for details at hiya.com.

9. What if my calls still get labeled after registration?
Registration isn’t a 100% whitelist. If your traffic suddenly shifts (volume, patterns) or if end users mark your calls as unwanted, carriers may re‑flag you. Always stick to best practices, watch your metrics, and re‑register new numbers proactively.