If your outbound calls show up as “at risk of spam” or “likely to be scammed,” it can be annoying if you’ve already done the “right thing” and implemented STIR/SHAKEN.
Here is the reality. STIR/SHAKEN is about caller ID authentication, not caller reputation. This allows network operators to determine whether a call is likely to be spoofed. However, carriers still use reputation analysis and user feedback to decide whether a call should be flagged or blocked. Even platform providers like Twilio explicitly state that SHAKEN/STIR will not remove the harassment flag.
For this reason, many teams are reducing their reliance on cold calls and shifting initial contact more toward messaging. For example, tools like Meera can compliantly target leads via SMS, qualify intent, and only direct serious prospects to your team, reducing the calling patterns that often trigger spam labels.
In this guide, we’ll explain what STIR/SHAKEN does, why calls are still flagged, and what you can do to fix flagging across all carriers.
What does STIR/SHAKEN actually solve and what doesn’t it?
STIR/SHAKEN is a technology specifically designed to digitally authenticate calls as they travel over cellular networks, eliminating the risk of illegal robocalls and caller ID spoofing.
However, it is important to note that this does not guarantee deliverability, response rates, or a clean reputation score, as carriers and call protection systems can still flag and filter calls using their own analytics. For example, AT&T explicitly distinguishes between “verified” indicators and calls flagged as spam or fraud risk, noting that calls at risk of spam may not receive verification indicators.
So when you ask, “We have STIR/SHAKEN, why are we still being flagged?”, the most logical answer is that even though you have authentication, your traffic still looks suspicious to carrier analysis, which leads to the flag.
What are the most common reasons why legitimate calls are still flagged?
Carrier labeling systems rely on a mix of behaviors rather than just one factor to determine whether a call appears trustworthy. This could be identity consistency, historical reputation, or even user feedback.
Companies can follow all standard protocols but will still be reported if the operator’s system analysis detects any of these factors and their call activity inadvertently indicates spam-like behavior. That’s why it’s important to understand the reason for the labeling before looking for technical solutions to this problem.
Here are some underlying issues you can address to resolve the issue:
Your calls have partial or weak attestation
Even in a STIR/SHAKEN world, calls can be signed with different attestation levels, commonly described as A, B, or C.
An A level means the provider knows the customer and the caller ID is authorized, while lower levels indicate less security. If your traffic frequently signals at B or C, carriers may still consider the calls to be higher risk, especially if they are combined with other suspicious signals.
Your calling patterns match spam behavior
Spam detection relies heavily on patterns. A high volume of calls from a number in a short period of time, short call durations, and low response rates can look like robocall behavior, even if you are a reputable business. This is especially common when teams use power dialers and go through lists quickly.
Your phone number will have a bad history or loss of reputation after porting
If your number was previously misused or if it was reactivated without a history, it can be flagged more easily. Porting can also disrupt reputation signals between ecosystems and temporarily increase labeling risk.
Caller ID data is inconsistent or incomplete
Carrier Analytics doesn’t just look at signatures. They also check that the caller ID looks consistent and trustworthy. Mismatched caller name information and inconsistent presentation can lead to suspicion.
End users and do not disturb apps report you
User feedback is important. If recipients mark your calls as spam, it can impact your reputation, and many consumer protection products use network analysis and machine learning to detect spam patterns.
How to diagnose the true cause of labeling?
Here are some steps you need to follow to diagnose the true cause of the label:
- Treat this like a funnel problem, not a telecom puzzle.
- Look at what has changed in the last 30 to 60 days. Did you increase call volume too quickly? Have you started using new numbers? Have you ported numbers? Have you changed your outbound provider?
- Look at the signal carriers that matter to you.
- Check your response rate and average call duration. If a large proportion of calls go unanswered and the average duration is very short, your traffic may resemble a nuisance call.
- Check your STIR/SHAKEN certification level. If you are not consistently getting strong attestation, you may have an upstream configuration or identity issue.
What actually fixes the “spam risk” label?
There are various approaches to address the problem of spam risk labeling, and we have listed some of the most effective solutions below:
Improve identity consistency and attestation quality
Work with your voice provider to increase the likelihood of a high school diploma if possible and to ensure that caller ID data is consistent. The attestation levels are specifically designed to express how trustworthy the caller ID is.
Customize call patterns to look human, not robotic
If you set up a new number and immediately reach high outgoing volume, you will often be rejected. Some providers specifically recommend warming up the numbers and gradually increasing the volume.
You also want to reduce behaviors that carriers interpret as nuisance calls, such as repeated calls of short duration.
Monitor and remediate reputation, not just authentication
STIR/SHAKEN helps prove calls are not spoofed, but analytics and reputation continue to drive labeling decisions. This is a widely discussed issue in the industry, including by reputation-focused vendors who emphasize that authentication alone is not a solution to labeling.
If your business relies heavily on outbound calls, proactive monitoring and remediation should be part of the operation and not a one-time setup.
Consider branded appeals and broader identity signals
Some carriers and industry discussions point to branded calls and richer caller identity data as an additional layer of trust beyond basic authentication.
The best tools to reduce reliance on cold calling and keep leads warm
A practical way to reduce the risk of spam flagging is to reduce the volume of repeated outbound attempts and shift early-stage qualification to channels that appear less intrusive.
Meera
If your team is calling a lot of leads just to find out who’s serious, an SMS-first qualification layer can relieve a lot of pressure on outbound calls. Meera is an AI SMS platform that can respond instantly, qualify intents through two-way SMS conversations, and route interested prospects to your team when they’re ready.
HubSpot workflows with messaging integrations
If your pipeline runs in a CRM like HubSpot, workflow automation combined with messaging integrations can help you respond quickly and keep follow-ups consistent without your team having to personally manage every thread.
Twilio for custom messaging and call flows
If you want full control, Twilio offers programmable building blocks for texting and calling. Twilio also notes that SHAKEN/STIR does not remove offending labels, which is a helpful reminder that deliverability requires more than just authentication.
Plivo for custom messaging and call flows
If you want full control over your voice and messaging infrastructure, Plivo offers programmable APIs for SMS and outbound calling. It enables teams to create custom call flows, manage caller ID configuration, and integrate directly into internal systems. As with other programmable voice providers, it is important to remember that STIR/SHAKEN authentication does not automatically prevent spam flagging, as carrier analytics and reputation signals still influence call handling.
In conclusion
STIR/SHAKEN is necessary, but it is not a guarantee that carriers will stop tagging your calls. Operator analytics, reputation signals, calling patterns and user feedback still determine whether a call is flagged as a spam risk.
The solution is usually a combination of stronger identity consistency, healthier calling patterns, and reputation monitoring. And for many teams, the biggest relief comes from moving early qualifying to SMS, so outbound calls focus on warmer prospects rather than heavy-handed dialing.
