If your calls show "Spam Likely" on the recipient's screen, or they return a busy tone, or they never seem to ring at all, a carrier is filtering them. This guide shows you how to confirm that, what to change, and how to get the label removed.
This guide is for agents making outbound calls and for admins who manage lines and number pools.
How carriers decide to label a number
Carriers do not read your script. They score the number's behavior.
Verizon, T-Mobile and AT&T each pass that scoring to an analytics vendor, TNS, First Orion and Hiya respectively, per Aloware's Voice Integrity registration.
The score comes from two inputs: what the people you call do afterwards, and what your calling pattern looks like from the network's side. Each carrier scores you separately, so a number can be flagged on one network while it is fine on another.
Eight behaviors account for nearly every label, and they fall into three groups. Find the group that sounds like your account, then go to the step that fixes it.
Who you are calling
The people on your list decide whether reports reach the carrier at all. Leads who genuinely opted in and want the call rarely report it, which is why this group is the largest single driver of spam labels. No setting compensates for it.
What carriers react to | How to check it | How to fix it |
Reports and blocks from the people you call | You cannot see these directly. Check whether a new lead list went into the dialer the week the flags started. | |
Leads who never opted in | Confirm where the list came from, and that texts go only to leads who consented |
How you are dialing
Carriers watch the volume and rhythm of your calls, not their content, and they watch any brand-new number closely for its first two weeks.
What carriers react to | How to check it | How to fix it |
More than about 100 calls a day from one number | Divide yesterday's dials by the number of active outbound numbers | |
A high share of calls under 30 seconds | Pull the share of calls under 30 seconds for the last two weeks | |
Repeated calls to the same lead in one day | Count callbacks per lead per day. Anything above two is scored against you | |
A sudden jump in volume on a quiet or new number | Compare dials per number before and after the number went live, or came back from rest |
How your numbers are set up and managed
These two are account housekeeping rather than calling behavior, and both are easy to miss. STIR/SHAKEN, the system carriers use to confirm you own the number you are calling from, is set up per number, and numbers that were never submitted are signed at a weaker confidence level and get filtered more.
What carriers react to | How to check it | How to fix it |
Numbers never submitted for STIR/SHAKEN | Look for numbers still unassigned, especially any added after the account was set up | |
Swapping numbers to escape labels | Check how often numbers were replaced over the last few months |
Expect a label at some point on any real outbound volume. What decides whether it sticks is the pattern behind it.
How to fix a flagged number
Fix what caused the label before asking the carriers to clear it. A number cleared while the cause is still there is flagged again within days.
Step 1: Confirm the calls are being filtered
Filtering does not always show as a label. It can appear as a busy tone, a call that rings out and never connects, or a call the recipient never sees.
Two signals tell you it is happening:
Calls marked Blocked by Carrier. Aloware applies this label in the Call Log and the Activity Feed using the carriers' SIP response codes.
Short, silent dials: calls that end in a few seconds with no voicemail and no ring on the lead's side.
A growing share of those means the calls are being blocked rather than ignored, which points to the number's reputation rather than the list. The rest of this guide applies.
Step 2: Check your number setup
These checks cost nothing and are the most common cause of busy tones and disconnected calls.
Submit every number for STIR/SHAKEN.
Each call is signed with an attestation level, A, B or C.
A means the carrier has verified you own the number, B means it recognizes your account but the number is not on your STIR/SHAKEN profile, and C means it only knows the call passed through its gateway.
Attestation is set up when your account is created, but numbers added later often sit unassigned and sign at B. Open your compliance settings, look for numbers not yet submitted, then select and submit them. Do this first whenever anyone reports busy tones.
Register the CNAM on every line.
Approval takes about 48 hours, then 30 to 45 days for carrier databases to update. Display is never guaranteed, because it depends on the recipient's carrier and plan: T-Mobile includes it for all postpaid customers, Verizon only on Call Filter Plus, and AT&T only on ActiveArmor Advanced. Register it anyway. It is free and it helps wherever it does display.
Register numbers with the carriers before they go into service.
Numbers can arrive already labeled, and a number that sits idle loses standing with the reputation vendors, so a new pool is not automatically a clean pool.
Register each number with the Free Caller Registry and the carriers' free forms (Verizon's voice spam feedback form, T-Mobile's call transparency site, AT&T through Hiya), and register again after any port, because the vendors key off routing changes. None of these forms tell you when a number gets flagged later.
Step 3: Check how many calls each number makes
Divide yesterday's total dials by the number of active outbound numbers. If the answer is anywhere near 100, the pool is too small, and the number will keep being flagged no matter how many times you clear it.
A practical working figure is 50 dials per number per day, which is the cap Aloware applies when correcting an account that has been flagged. Sizing against 50 rather than 100 leaves room for a busy day.
Team size | Daily dials | Numbers needed at 50 dials each |
3 agents at 60 dials | 180 | 4 |
8 agents at 80 dials | 640 | 13 |
20 agents at 100 dials | 2,000 | 40 |
Aloware pool sizes: a Major Cities pool tops out around 88 to 90 numbers, and a Nationwide pool at up to 300, typically 260 to 270 delivered depending on carrier inventory.
Two things to check alongside the total:
Agents dialing from a personal line.
One agent on one number puts their entire day's volume through it. Route outbound calls through the pool instead.
How the pool is weighted.
Pull the last one to three months of call volume by state. Put more numbers in the states you call most, and one number per state elsewhere so occasional calls still show a local area code. The number count and the price stay the same.
Step 4: Fix the calling pattern
Setup protects a number. What agents do keeps it protected.
Leave a voicemail on every unanswered call.
It turns a two-second dial into a real contact, on the carrier's books and on the lead's phone, and it trains the iOS and Android filters, so a lead who has a voicemail or a text from you sees a "Maybe: [name]" prompt instead of a silently filtered call. Keep it to 15 to 30 seconds, and always name your company and give a callback number.
Federal telemarketing rules require the company name and the callback number on outbound sales calls. Where agents will not record live, use voicemail drops, which register duration on the network the same way. Drops go only to leads with written consent.
Space out the callbacks.
At most a double dial, then six to eight hours before the next attempt that day, then 24 hours, then 48. Never six attempts in a day, and never the same lead two or three times every day.
Florida and Oklahoma laws prohibit more than three commercial solicitation calls in 24 hours on the same subject, regardless of the phone number used. Check the rules for the states you call.
Text opted-in leads before you call.
Your number is then already on their phone when it rings. On Aloware plans, agent calls and texts on US and Canada local numbers are unlimited, so this costs nothing beyond the carrier's per-segment pass-through fee.
Watch automated volume too, because opt-outs from CRM workflows feed the same brand reputation your calls trade on.
Check where the list came from.
Leads who genuinely opted in and want the call do not generate reports. Leads who do not remember opting in do.
If flags started the same week a new list went into the dialer, that list is the cause, and remediation will not hold while you keep calling it. Scrub disconnected numbers before they reach the dialer as well, because a run of dials to dead lines tells the analytics engines the list was bought rather than built.
Track call duration.
Watch the share of calls under 30 seconds and under two minutes, plus average talk time. When the short-call share climbs, the carrier is already reacting.
Step 5: Request remediation
Once Steps 2 to 4 are in place, use NumberGuard to find labeled numbers and submit them to the carriers.
Review the NumberGuard scan.
Escalate for remediation any number flagged three weeks running.
Allow two to three days for T-Mobile and AT&T, based on Aloware's remediation experience.
Allow two to three weeks for Verizon, which holds the number in a probation state. The number keeps appearing on scans during that period. That is Verizon's process, not a failed submission.
No carrier publishes a guaranteed timeline, and the Free Caller Registry states that registration does not guarantee redress.
Remediating before the practices are fixed does not hold. A number cleared on Tuesday is flagged again by Friday if the same volume and the same cadence continue.
Step 6: Rest a number that keeps getting flagged
Do Not Use marks a number as unavailable for outbound calling without removing it from your account. It sits in the line's phone-number list, next to transfer and unrent.
The number stays rented and still receives inbound calls, so leads who saved it can still reach you.
Set the number to Do Not Use for about a week.
Bring it back at 10 to 20 calls a day.
Move to 40 to 60 calls a day.
Return to normal volume.
Ramp gradually, because a jump from zero to full volume is the same spike carriers watch for. Inside a Local Presence pool you cannot control the ramp, so rest pool numbers more sparingly.
When to change a number
Replace a number only after two remediation cycles and two to three months of continued flagging despite everything above. Never replace a whole pool on a schedule.
Swapping numbers to escape labels is a pattern the analytics vendors detect, a freshly rotated number can be tagged within a handful of calls, and doing it repeatedly teaches the carriers to distrust the whole account.
If a number changed hands before you got it, Twilio's guidance is to rest it at least 45 days before dialing from it.
Verifying it worked
Check these after a remediation cycle:
The number no longer appears on the NumberGuard scan. Allow for Verizon's probation period before treating a repeat appearance as a failure.
Blocked by Carrier entries have dropped.
Dials per number are staying well below 100.
The share of calls under 30 seconds is falling.
Voicemails are being left on unanswered calls, and a random sample includes the company name and a callback number.
What each tool does and does not do
Tool | What it does | What it does not do |
Spreads traffic across many numbers and matches the lead's area code, which lifts pickup rate | Nothing for a number that is already labeled | |
Scans your numbers against AT&T, T-Mobile and Verizon, detects spam labels and submits them for remediation | Cannot outrun poor calling practices; a cleaned number re-flags if the behavior continues | |
Free display name on the line | Not guaranteed to show; depends on the lead's carrier and plan | |
Verified name and logo on T-Mobile and Verizon; a registered brand is harder to label | Does not remove an existing spam label; not available on AT&T. On Verizon a risk label takes precedence and the brand does not display | |
Attestation the carriers require before they trust the call | Not a spam-label fix; weak attestation causes filtering and busy tones |
None of these replaces the steps above. Branded Calling gives you no visibility into whether numbers are flagged, so pair it with NumberGuard if you use it.