Why Your Business Calls Show as Spam Likely (and the Fix)

You call a prospect back within five minutes of their inquiry, and your number shows up on their screen as "Spam Likely." They don't answer. Nobody answers. For a business that lives on outbound calls — sales teams, medical offices confirming appointments, contractors scheduling site visits — a spam label can quietly cut your answer rate in half. The frustrating part: you did nothing wrong. Your calls got caught in the machinery built to stop actual robocallers.

This guide explains what STIR/SHAKEN is, what attestation levels actually mean, why legitimate business numbers get flagged, and the concrete steps that get the label removed.

What STIR/SHAKEN actually is

STIR/SHAKEN is a pair of technical standards — Secure Telephone Identity Revisited (STIR) and Signature-based Handling of Asserted information using toKENs (SHAKEN) — that let phone carriers cryptographically sign a call as it leaves their network and verify that signature when it arrives at the destination network. The point is to stop caller ID spoofing, the trick robocallers use to display a fake number.

Congress made it mandatory. The TRACED Act, signed into law in December 2019, directed the FCC to require STIR/SHAKEN across US voice networks. Large voice providers had to implement it on their IP networks by June 30, 2021, and the FCC extended the framework to smaller providers by June 30, 2023. Every provider must also file in the FCC's Robocall Mitigation Database; since late September 2021, carriers have been required to refuse traffic from providers that never filed.

Here is the important nuance: STIR/SHAKEN does not label calls as spam. It attaches an attestation — a signed statement about how well the originating carrier knows the caller. Carriers and their analytics partners then use that attestation, along with your calling patterns, to decide what to display.

Attestation levels: A, B, and C

When your carrier signs an outbound call, it assigns one of three attestation levels:

• A (Full attestation). The carrier knows who you are, originated the call itself, and has verified you are authorized to use the number you are calling from. This is the level you want on every call.
• B (Partial attestation). The carrier knows the customer who placed the call but cannot verify their right to use the specific number displayed. Common when a business brings its own numbers to a provider that never confirmed ownership, or when calls route through a PBX that inserts a different caller ID.
• C (Gateway attestation). The carrier only knows where the call entered its network — for example, an international gateway — and can vouch for nothing else. C-attested traffic is treated with the most suspicion.

A- and B-attested calls both pass signature verification, but analytics engines weigh them differently. A business making normal call volumes with A attestation rarely gets labeled. The same business pushing B- or C-attested traffic starts every call with a credibility deficit.

Why legitimate calls still get labeled "Spam Likely"

The labels you see on a phone screen come from analytics companies working with the major mobile carriers. Each of the big three uses a partner: AT&T works with Hiya, T-Mobile with First Orion, and Verizon with TNS. These firms score calls using attestation level, crowd-sourced complaint reports, and behavioral signals. The patterns that trigger flags include:

• High volume, short duration. Hundreds of calls a day that mostly last under 30 seconds looks like a robocaller, even if it is your appointment-reminder line.
• Low answer rates. If most of your calls ring out, the algorithms read that as unwanted traffic — a self-reinforcing loop once a label appears.
• Number rotation. Cycling through caller IDs to "stay fresh" is exactly what spammers do. It destroys the calling history that protects a number.
• User complaints. A handful of "report spam" taps on a low-volume number can outweigh months of clean history.
• Weak attestation. B or C attestation doesn't cause a label on its own, but it lowers the bar for everything else.

How to find out if your number is flagged

Call your own business lines from personal phones on each major network — AT&T, T-Mobile, and Verizon can each label the same number differently. Check both the label ("Spam Likely," "Scam Likely," "Telemarketer") and the name displayed. If your outbound calls show a wrong or missing name, that is a separate but related problem: your CNAM (caller ID name, limited to 15 characters) was never set or never propagated.

How to fix a spam label

1. Register with the Free Caller Registry

The three analytics firms operate a shared intake portal at freecallerregistry.com. One submission sends your business name, numbers, and calling purpose to Hiya, First Orion, and TNS. Registration is free, and for legitimate businesses it is the single highest-impact step. Expect the review to take days to a few weeks, and re-register when you add numbers.

2. Confirm your calls get A attestation

Ask your voice provider directly: "Do my outbound calls carry A-level attestation?" If they can't answer, or your numbers were ported in without ownership verification, that is worth fixing. fvoip signs outbound calls with full attestation for numbers on our network, including numbers you port over from another carrier — porting transfers ownership, so ported numbers qualify for A attestation just like new ones.

3. Set your caller ID name

Have your provider register a consistent 15-character CNAM for every outbound number. A call that displays "SMITH DENTAL" gets answered; an unlabeled number from an unfamiliar area code does not.

4. Fix the calling patterns

Spread outbound campaigns across business hours instead of blasting at 9:00 a.m. sharp. Leave voicemails — completed calls with real duration look human. Don't rotate numbers; let each number build history. And give people a way to reach you back: a callback number that answers (a multi-level auto-attendant works fine) signals legitimacy to both algorithms and customers.

5. Dispute stubborn labels directly

If a label persists after registration, each analytics firm accepts disputes through the same registry portal. Document your business identity and calling purpose. Persistent mislabels on ported numbers sometimes trace back to the number's previous owner — history follows the number, which is a good reason to check a number's reputation before you adopt it.

Three myths worth clearing up

"I'll just get a new number." Tempting, and usually a mistake. A brand-new number has no calling history, so it starts with zero reputation — and if your calling patterns triggered the label, the new number inherits the problem within weeks. Worse, abandoning a number your customers know costs you callbacks. Fix the root cause instead; number changes are a last resort for numbers with a poisoned history you didn't create.

"Spam labels only affect mobile calls." The visible label appears mostly on mobile screens, but the same analytics scores feed carrier-level blocking decisions on both mobile and landline networks. The FCC permits carriers to block calls that analytics flag as highly likely to be illegal, which means a badly scored number can see calls silently fail, not just display badly.

"Attestation A guarantees no label." It doesn't — attestation is one input among several. A-level attestation plus registered caller ID plus sane calling behavior is what keeps a number clean. Any one alone is insufficient, which is why the fix list above is a list.

What this means when choosing a phone provider

STIR/SHAKEN compliance is now table stakes, but providers differ in the parts you feel: whether your calls get A attestation, whether CNAM management is handled for you, and whether support will actually walk you through a registry dispute. Those questions belong on your evaluation checklist next to price and features.

fvoip includes e911, verified caller ID, and US-based 24/7 support on every plan, with no contracts and a 30-day money-back guarantee — so if your answer rates don't recover, you're not locked in. If spam labels are costing you business today, start with the Free Caller Registry, then make sure the carrier behind your calls is signing them properly.