
Strategies to Continue Combatting Call Blocking and Flagging

Scam-Likely, Spam Risk, Fraud Risk, Potential Fraud, Potential Spam. Pick a warning…
For any business with contact center agents trying to reach leads, one thing is clear: connecting with potential customers is increasingly difficult. This challenge is not new to outbound call center managers, but it remains one of their top concerns.
After investing in consent-based leads, it’s frustrating when legitimate outreach encounters flagged or blocked caller IDs. Unsurprisingly, this causes contact rates to decline.
Contact centers should adopt new strategies to remain competitive in 2025 by:
Understanding why outbound calls are flagged and blocked.
Avoiding dialing practices that trigger spam risk flags.
Employing advanced call center management strategies to improve contact rates.
Managing caller ID reputation to protect outbound dialing efforts.
This trend article is part of the series, “Contact Center Trends,” helping you stay current with issues, technologies, best practices, and strategies that impact your business. Our aim is to provide tools and guidance that will improve productivity, efficiency, and sustainable profitability for your sales and lead generation team.
Why are legitimate calls being flagged or blocked?
Robocalls remain a significant issue, with billions of spam calls placed annually. By late 2024, over 55 billion robocalls had been placed to American recipients, with approximately half deemed fraudulent. To counteract this, legislation such as the TCPA, TRACED Act, and STIR/SHAKEN standards has continued to evolve, empowering consumers and carriers to block unwanted communications.
However, even legitimate calls often get flagged due to:
Carrier Algorithms: These black-box systems identify and flag calls that appear suspicious, such as those with high call volumes from a single number.
Consumer Reporting: Apps like Robokiller, Nomorobo, and Truecaller allow users to label numbers as spam, often targeting legitimate businesses.
Pre-Flagged Numbers: Some call centers are issued numbers already flagged as spam due to prior misuse by others.
Despite efforts to maintain compliance and use high-quality leads, these factors persist as obstacles for legitimate contact centers.
5 proactive strategies for contact centers in 2025
While no single solution exists to combat flagged and blocked calls, outbound call centers can employ several strategies to minimize disruptions and improve contact rates.
1. Smarter outreach strategies
Aggressive, outdated dialing practices no longer work. Instead, next-gen call centers should:
Prioritize Lead Quality: Focus on high-intent leads and use predictive dialer software to avoid over-calling low-intent contacts.
Use Omnichannel Outreach: Incorporate email and SMS alongside strategic call cadences, ensuring a balanced and effective approach.
Leverage Automation: Deploy tools that automate outreach sequences across multiple channels, enhancing efficiency and contact rates.
According to Convoso CEO Nima Hakimi, “Automating outreach processes with an omnichannel approach that combines texting, emailing, and calls can significantly boost your chances of connecting with consumers.”
2. Identify blocked and flagged caller IDs
Caller ID reputation management is critical in 2025. Use dialer capabilities to:
Monitor DID Health: Track flagged and blocked phone numbers in real-time to address issues promptly.
Rest or Replace DIDs: Swap out flagged numbers before they harm KPIs and overall efficiency.
Tools like ClearCallerID Pro™ help prevent flagged or blocked numbers with proactive tools and automatic remediation and streamline caller ID management to increase call deliverability and real-time, easy-to-use analytics with greater visibility.
3. Dial smarter, not harder
Real-time analytics can help call centers optimize list performance by:
Monitoring List Efficiency: Identify low-performing lists and adjust dialing strategies to maximize ROI.
Analyzing Metrics at the Micro Level: Review revenue per rep, per hour, and per list to make data-driven decisions.
Stopping Inefficient Campaigns: Pause low-contact-rate lists to prevent further damage to caller ID reputations.
4. Manage caller IDs based on call volume and geography
Carriers’ algorithms scrutinize call patterns and volumes. To avoid spam flags:
Limit Calls Per ID: Keep daily call volumes per number under 50.
Distribute Call Volume Geographically: Use data to allocate DIDs across regions, ensuring optimal performance.
5. Establish caller legitimacy
Legitimate identification is key to avoiding spam labels. In 2025, call centers should:
Register DIDs: Work with analytics companies that report data to carriers.
Implement Caller ID Branding: Display verified business names to reassure recipients.
Register SMS Campaigns: Use The Campaign Registry to enhance deliverability.
Looking Ahead
The battle against call blocking and flagging will continue to evolve as technology and regulations change. By implementing smarter strategies, leveraging advanced tools, and focusing on compliance, outbound call centers can maintain strong contact rates and ensure profitability in 2025 and beyond.
Why are your legitimate calls being flagged or blocked?
Although they slowed down in 2020 during the beginning of the COVID-19 pandemic, robocalls have spiked in the years since and continue to plague millions of Americans. As of the beginning of December 2023, over 51 million robocalls have been placed to American recipients. According to one estimate, about half of these calls are illegal, fraudulent calls. In response to this proliferation of spam calls, both consumers and carriers have taken action to fight back against unwanted communications—and these will continue to affect call centers in 2024. We’ve seen the introduction of legislation, including the TCPA and the TRACED Act, and a host of rules aimed at protecting the consumer (e.g., STIR/SHAKEN). Many call centers make great efforts to work with compliant data and to use dialing practices in compliance with regulations. Unfortunately, despite these efforts, even legitimate calls may not reach the respective caller. Stuart Discount, CEO of SMD Contact Center Consulting and former CEO of PACE, described the dilemma: “Outbound dialing has decreased almost every year since Do-Not-Call (DNC) back in 2003, but it’s really getting bad now because legitimate outbound callers are being dwarfed by robocallers – their calls aren’t getting through. In some cases, they’re getting blocked by the carriers because they’re being labeled as spam when they are not spam.” In a video chat with Jesse Daniels, VP of Sales at One Health Direct, he mentioned how devastating it is to have calls flagged as a spam risk, especially for a legitimate nationwide business dependent on reaching consumers.
“I read a statistic that said there’s about a 6% chance that [customers] are going to pick up the phone if they see “Scam Likely.” That’s it. So if that’s showing up on their cell phones, they are not picking up the phones. And if people are not picking up the phones, I can’t make money and I can’t keep my business afloat.”
Understanding factors that contribute to call blocking or flagging
This flagging of legitimate calls is a consequence, according to Convoso CEO Nima Hakimi, of carriers’ black-box algorithms that determine whether or not a call is spam. As carriers have increasingly taken matters into their own hands, it’s these algorithms that are having an outsized effect on call center performance. “Unfortunately, [because algorithms are kept secret] nobody has the exact formula behind why your calls get flagged,” Hakimi says. However, there are various factors that can contribute to the likelihood of calls being flagged as a spam risk or blocked altogether:
Telco carriers’ algorithms attempt to determine when calls appear to have been placed by an automated system rather than manually. “One of the things that gets you flagged is a bad call strategy,” says Josh Friend of Insellerate. “So if a single number makes 1,000 calls in a day, a telco carrier is going to start to go, ‘Who calls that many people in a day?’”
Consumers can download third-party apps to block calls such as Robokiller, Nomorobo, Hiya: Spam Phone Call Blocker, Truecaller, YouMail Voicemail & Spam Block and more.
Consumers can simply report specific numbers as spam or scam through their smartphones and block these numbers.
STIR/SHAKEN standards aimed at eliminating spoofed caller IDs aren’t necessarily a way to block calls. However, ensuring that your calls receive a high attestation rating can help you avoid being blocked.
Because of how widespread the issue of flagging has become, some call centers are receiving new caller IDs that are already flagged.
What can your call center do about blocked and flagged calls?
There is no single solution to avoiding flagged or blocked calls. But there are a few steps sales and lead gen teams can and should take to minimize the blow to contact rates. The trend for outbound call centers in 2024 is to employ the right strategies to reduce the risks that your calls will be blocked or flagged as spam.
Smarter Outreach Strategies
Gone are the old school ways of hammering away at leads till you reach a good prospect. “Dialing your leads to death, over and over and over, is no longer a working strategy,” says Nima Hakimi. This strategy, he says, will result in your calls being blocked or labeled as spam. To understand the smarter strategies used by next gen call centers, begin by assessing the quality of the leads you’re dialing. If you have low-intent leads, be cautious how aggressively you set up your agents to call them. Instead, plan your campaigns to rest the numbers that don’t reach anyone by scheduling a cadence spaced over time. Sophisticated predictive dialer software can support responsible dialing, with tools that automatically rest lists or leads based on their intent levels and prior dispositions, and employing a smart redial/recycle logic for optimal lead management. For high intent leads, leverage an omnichannel approach that includes email and outbound SMS solutions, with strategic call cadences and features like smart voicemail drops to reach out to those consumers in the best way possible. According to Hakimi, “You want to have strategies in place that automate the outreach process and an omnichannel approach where you set up a sequence of events that uses texting, emailing, and calls.”
Identify blocked and flagged Caller IDs
Caller ID reputation management is key to avoiding the negative effects of call blocking and flagging. To help manage your DID health, look for your dialer’s capability to track flagged and blocked phone numbers and to take action before critical KPIs are impacted. “What’s even more important [than just knowing calls are flagged or blocked] is learning about flagging and blocking in as close to real time as possible,” says Nima Hakimi. With this information you can quickly fix the issue. “You can rest DIDs or replace them with clean numbers. You can minimize the damage done.”
ClearCallerID™️ for Better DID tracking
ClearCallerID™️ is a tool that monitors the health of caller IDs used by outbound call centers to dial prospects, enabling them to track numbers that are blocked by carriers and consumers as well as numbers flagged as spam risk. By knowing their caller ID performance, dialer admins can take action by swapping out DIDs before flagging and blocking effect efficiency and profitability. Learn more about ClearCallerID.
Dial smarter, not harder
Another critical management strategy for outbound call centers is to monitor list performance in real time. Data analytics show you insights about what’s really going on with your lists – are they making money or not? If your agents are dialing a list that’s getting a low contact rate, and you can find that out as it’s happening, you can change course and stop using that list for a period. Powerful reporting tools are one of your most important assets for managing productivity and driving profitability. In the webinar The Next Generation Call Center, Nima Hakimi talked about analyzing the performance of your lists as part of your dialing strategy to handle call blocking.
“Calls are being blocked. If you don’t have a good sound strategy in place around your high intent versus low intent leads, your caller IDs are likely to get flagged. You’re going to get calls blocked without you even knowing about it. Which is why it’s really important to look at the performance of your list: How many times are you calling it, what is the revenue like by rep, by hour, by list – really going to that micro level, to see when there’s a dip. And be able to make those decisions in real time. I believe that’s one of the biggest problems that call centers have is that they don’t have the ability to look at information at a granular level…For example, if you’re dialing through a list and there’s no revenue being generated at a specific hour, then turn that list off.”
Managing caller IDs based on call volume and geography
In 2024, outbound sales and lead gen teams need to proactively manage the reputation of their Caller ID numbers (DIDs). Call centers that dial a lead in excess will wind up with their caller ID labeled as spam. Your dialer should have the capability to analyze call patterns and call volume, and then use that data to recommend how many caller ID numbers you should use, specifically indicating how many to use in each area code to minimize the chances of your caller ID being flagged as a scam. Nima Hakimi recommends limiting yourself to 50 calls per caller ID each day as a rule of thumb.
Take proactive steps to show your identity is legitimate
A strong caller ID reputation goes a long way to identify you as a legitimate caller in the eyes of the major carriers. Legitimate callers are more likely to avoid becoming victim to blocked or flagged calls. Consider these additional tactics to establish your legitimacy:
Register your DIDs through the analytics companies that report data to the major carriers.
Incorporate caller ID branding tools which will show recipients that the call is legitimate.
Register SMS campaigns with Campaign Registry to improve delivery.
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