### Answer There are a few common reasons why outbound calls get marked as spam: High call volume without warmup – When a number experiences a high outbound call volume spike without any warmup and/or has a low pickup rate, it might be marked as spam by carriers. [(1) ]() High call frequency – If the number of outbound calls is high in a short time period, carriers will begin flagging numbers with spam labels. [(2) ]() Low engagement rates – Low engagement could be seen as spam behavior by carriers. Customer complaints – When customers file complaints or block a number, carriers are more likely to label that number as spam. Remediation steps: 1. Purchase a new number and warm it up – Slowly add outbound traffic to it before pouring all traffic to it. [(1) ]() 2. Increase your pickup rate – See the [Increase Pickup Rate]() guide. 3. Register your number with spam remediation – Use the verified phone number feature. See [verified phone number]() . 4. Monitor your caller ID reputation – Check your outbound call log to see if the call was not connected due to SIP error code 608, which means it's rejected due to being marked as spam likely. [(3) ]() 5. Manage call cadence – Spread out your follow-ups, rotate call times, and balance calls with other touchpoints.

​ To learn more, see the sources I considered: [[1] Debug outbound connection issues](https://docs.retellai.com/reliability/debug-outbound-call) [[2] Why Enterprise Security Matters for Voice AI | Retell AI](https://www.retellai.com/blog/why-enterprise-security-is-important-for-voice-ai-technology) [[3] iOS 26 Call Screening: Best Practices for Outbound | Retell AI](https://www.retellai.com/blog/ios-call-screening) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.