Frequently asked questions about outbound calls blocked or tagged as spam
When making outbound calls from Zoom Phone, your call may be blocked or tagged as spam by the receiving party's phone service or carrier. This article answers common questions to help you understand why this happens and what you can do about it.
Why are my outbound calls being blocked or tagged as spam?
Carriers are increasingly implementing call-blocking programs to protect consumers against abusive robocalls. In the United States, carriers like AT&T, Verizon, and T-Mobile block or tag calls as spam when they detect robocalling characteristics, such as high-volume, short-duration calls originating from a single number.
Other possible reasons your call is being blocked include:
- The receiving party is using a third-party database service that's blocking your call, such as Nomorobo.
- The receiving party is using a third-party phone service with filters or rules that are blocking your number, such as rules that block all callers with a certain number prefix.
- Your number has been flagged by an analytics provider such as TNS, Hiya, First Orion, or Neustar.
How do analytics providers decide if a call is spam?
Carriers and analytics providers use a combination of internal analytics, customer call-blocking data, and complaint tracking to determine whether a call is spam or fraudulent. Third-party analytics companies — such as TNS, Hiya, First Orion, and Neustar — also feed information into carrier systems. While these measures help identify many fraudulent calls, false positives can occur.
What can I do to stop my calls from being tagged as spam?
You can proactively register your number with analytics providers and contact carriers directly to request that your number be allowed. For example, if you use your Zoom Phone number to make frequent, short outbound calls to remind clients of appointments, these may be categorized as fraudulent calls by wireless carriers. Registering your number helps analytics providers recognize your calls as legitimate.
Which analytics providers should I register with?
You can report your number to the following analytics providers:
- Free Caller Registry: Covers First Orion, Hiya, and TNS. This free portal helps you reach the analytics companies that support the major wireless carriers in the US. Note that analytics companies will review your request and may still flag calls depending on their own analytics or research.
- Call Transparency: Used for T-Mobile and supports bulk reporting (First Orion).
- Hiya: Used for AT&T.
- TNS: Used for Verizon, Comcast, Sprint, Spectrum, and others.
- Neustar: Refer to the contact information under Communications, Robocall Mitigation.
Which carriers can I contact directly to remove a spam label from my number?
If you know which carrier is incorrectly labeling your calls, you can contact them directly. The table below lists common carriers and the call labels they use:
| Company | Call label |
|---|
| Altice | "Fraudulent Call" or caller ID name (CNAM) prepend of "Spam?" or "Robo?" |
| AT&T | "Spam Risk" or "Fraud Risk" |
| Comcast | "Blocked – High Spam Risk" or CNAM prepend of "Spam?" |
| C-Spire | "Potential Spam" |
| Fidelity | "Fraudulent Call" or CNAM prepend of "Spam?" |
| Frontier | "Robocaller" |
| Lumen | "Robocaller" |
| Midco | — |
| Spectrum | "Spam Likely" |
| Telzio | "Fraudulent Call" |
| T-Mobile | "Scam Likely" |
| Truecaller | "Spam" |
| US Cellular | "Potential Spam" |
| Verizon | "Potential Spam" |
| Windstream | "Fraudulent Call" or CNAM prepend of "Spam?" |
Are there robocall database services I can contact as well?
Yes. If you believe a third-party robocall database service is blocking your number, you can contact them directly to request that your number be allowed. Common services include: