Mobile carriers use several parameters (including 3rd-party spam engines) to score calls and mark them as "Spam Likely". Depending on the network, flagged calls may be: - Shown to the recipient with a spam label
- Sent directly to the recipient's voicemail box
- Routed to a false answer service (FAS) where the call is connected with no audio or a fake voicemail box.
Why calls are labeled this way or how they are routed is not publicly shared. Every network uses proprietary algorithms that set unique weights on different parameters. Because these systems are designed to question all calls and there is no universal whitelist to manually override them, you must build trust for your phone number over time. 1. Have recipients mark your calls as "Not Spam"Ask friends, family, or clients to unflag your calls. If your calls do not appear in their standard call history, they can locate and allow them inside their carrier's spam protection app: Note: Wireless networks require multiple independent "Not Spam" reports over time to remove a flag. 2. Report false spam flags directly to carriersIf you know which provider the person you are trying to reach uses, you can submit a direct unflagging request: 3. Register with the Free Caller Registry (For Businesses)If you are a business or organization, submit your number(s) to the Free Caller Registry. This distributes your caller information across major analytics providers (Hiya, TNS, and First Orion) to help prevent spam misclassification across all major networks. Important: Spam engines score calls based on many metrics. Information collected through the Free Caller Registry is just one parameter—it does not automatically whitelist your traffic. | 
