What Kinds of Problems Do You Typically Un- cover?

February 12, 2026

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We see the same category of problems repeatedly, but in different combinations and with different severity. These aren’t surface-level issues. They’re systemic problems that tools miss and that responsible operators often don’t see until reputation starts degrading visibly.

Authentication Misalignment

This is more common than it should be. A company configures SPF, DKIM, and DMARC correctly according to their ESP’s documentation, but doesn’t account for the actual flow of their mail. They might be sending email through multiple ESPs without realizing it, or they changed email providers six months ago and never cleaned up old DNS records, or they’re sending from a domain but not aligned the DKIM to that domain.

The result: authentication technically works, but isn’t as strong as it should be. Mail that should be passing DKIM alignment fails occasionally. SPF includes too many providers. DMARC policy is set to monitoring when it should be enforcing.

We also see authentication gaps in more complex infrastructure. A company might have correct DMARC alignment on their marketing domain, but not on the subdomain they use for transactional email. They might have proper authentication on cold email sending, but not on their webhook-based transactional infrastructure.

DNS and Infrastructure Gaps

Your DNS tells a story about your mail infrastructure. Sometimes that story is incomplete. Missing reverse DNS (PTR records). IPs that don’t match the domains they claim to represent. Incomplete or outdated SPF records that list providers you haven’t used in years. These gaps matter less for technical correctness and more for reputation signals that mailbox providers use to assess trustworthiness.

We’ve also seen cases where companies have infrastructure gaps they weren’t aware of: they think they’re sending from one IP but their ESP is distributing across multiple IPs without proper reputation separation. They think their IP is dedicated but it’s shared with other senders. They have multiple sending IPs but only one is warmed.

Volume and Cadence Misalignment

Mailbox providers care deeply about consistency. When you change your sending volume dramatically, or shift your sending time, or change your target audience geography, those changes get noticed. They trigger higher scrutiny of your mail.

We see companies that ramped volume too aggressively relative to their domain’s sending history. They send 5,000 emails a week for six months, then try to jump to 50,000 a week. The mailbox provider sees this as unusual behavior and filters more of the mail until reputation stabilizes.

We see seasonal senders who restart sending after a long pause without accounting for how reputation degrades. A newsletter sender takes a three-month break, restarts in month four, and gets filtered more aggressively because the mailbox provider has forgotten them.

We see companies that shift their target audience without realizing the reputation impact. A B2B SaaS company starts targeting a new geography, and gets filtered more aggressively there because the mailbox provider doesn’t have established reputation for them in that region.

Complaint Risk and List Quality

Most companies monitor complaint rates, but few monitor complaint risk – the likelihood that unengaged subscribers will complain if you keep mailing them. A list might look fine by complaint metrics but be heading for a complaint spike if you keep mailing it without re-engagement efforts.

We assess list age, engagement rates, subscription method, and re-engagement patterns to identify list quality problems before they become visible as complaint spikes. We also look at whether complaint increases are being handled properly (removing complainers, analyzing complaint patterns, adjusting sending if needed).

Cold email is particularly prone to complaint risk. A sender might be getting a 0.5% complaint rate (which seems fine) while actually mailing 80% of people who are not engaging (which is a complaint spike waiting to happen).

Language Patterns and Content Issues

Modern spam filters use machine learning to detect patterns in content. They’re looking for things like: consistent use of high-pressure language, repeated selling patterns, headers that don’t match content, links that don’t match visible text.

We assess your content patterns for signals that modern filters watch for. Sometimes the problem is obvious (you’re using all-caps subject lines, or your copy has the feel of classic spam). Often it’s subtle (you’re using the same urgency pattern in every subject line, or your calls to action trigger filters in certain mailbox providers, or your links look suspicious to reputation algorithms).

These patterns compound across campaigns. A single email with slight red flags passes through. Fifty emails from the same sender all with the same pattern triggers filters.

System Interaction Problems

Sometimes the problem isn’t any single element, but how elements interact.

Your cold outreach has high complaint risk, which damages your domain reputation. That reputation damage affects your marketing email and transactional email. Your complaint rate is technically fine, but your unsubscribe rate is high, and high unsubscribe is an engagement signal that triggers filtering.

We look for these system-level interactions. A diagnostic often surfaces a primary problem (usually reputation or behavior related) that’s masking or compounding secondary problems. Fix the primary problem and the secondary problems sometimes resolve themselves.

We’d love to learn more about your business, email deliverability and outreach goals, and see if we might be able to help.

Whether you have questions about what we do, how Protocol works, or you’d just like to pick our brains on some of our best practices, we’d be happy to chat.

Schedule a call with our Revenue Director, Chrisley Ceme.

Talk To Chrisley

We see the same category of problems repeatedly, but in different combinations and with different severity. These aren’t surface-level issues. They’re systemic problems that tools miss and that responsible operators often don’t see until reputation starts degrading visibly.

Authentication Misalignment

This is more common than it should be. A company configures SPF, DKIM, and DMARC correctly according to their ESP’s documentation, but doesn’t account for the actual flow of their mail. They might be sending email through multiple ESPs without realizing it, or they changed email providers six months ago and never cleaned up old DNS records, or they’re sending from a domain but not aligned the DKIM to that domain.

The result: authentication technically works, but isn’t as strong as it should be. Mail that should be passing DKIM alignment fails occasionally. SPF includes too many providers. DMARC policy is set to monitoring when it should be enforcing.

We also see authentication gaps in more complex infrastructure. A company might have correct DMARC alignment on their marketing domain, but not on the subdomain they use for transactional email. They might have proper authentication on cold email sending, but not on their webhook-based transactional infrastructure.

DNS and Infrastructure Gaps

Your DNS tells a story about your mail infrastructure. Sometimes that story is incomplete. Missing reverse DNS (PTR records). IPs that don’t match the domains they claim to represent. Incomplete or outdated SPF records that list providers you haven’t used in years. These gaps matter less for technical correctness and more for reputation signals that mailbox providers use to assess trustworthiness.

We’ve also seen cases where companies have infrastructure gaps they weren’t aware of: they think they’re sending from one IP but their ESP is distributing across multiple IPs without proper reputation separation. They think their IP is dedicated but it’s shared with other senders. They have multiple sending IPs but only one is warmed.

Volume and Cadence Misalignment

Mailbox providers care deeply about consistency. When you change your sending volume dramatically, or shift your sending time, or change your target audience geography, those changes get noticed. They trigger higher scrutiny of your mail.

We see companies that ramped volume too aggressively relative to their domain’s sending history. They send 5,000 emails a week for six months, then try to jump to 50,000 a week. The mailbox provider sees this as unusual behavior and filters more of the mail until reputation stabilizes.

We see seasonal senders who restart sending after a long pause without accounting for how reputation degrades. A newsletter sender takes a three-month break, restarts in month four, and gets filtered more aggressively because the mailbox provider has forgotten them.

We see companies that shift their target audience without realizing the reputation impact. A B2B SaaS company starts targeting a new geography, and gets filtered more aggressively there because the mailbox provider doesn’t have established reputation for them in that region.

Complaint Risk and List Quality

Most companies monitor complaint rates, but few monitor complaint risk – the likelihood that unengaged subscribers will complain if you keep mailing them. A list might look fine by complaint metrics but be heading for a complaint spike if you keep mailing it without re-engagement efforts.

We assess list age, engagement rates, subscription method, and re-engagement patterns to identify list quality problems before they become visible as complaint spikes. We also look at whether complaint increases are being handled properly (removing complainers, analyzing complaint patterns, adjusting sending if needed).

Cold email is particularly prone to complaint risk. A sender might be getting a 0.5% complaint rate (which seems fine) while actually mailing 80% of people who are not engaging (which is a complaint spike waiting to happen).

Language Patterns and Content Issues

Modern spam filters use machine learning to detect patterns in content. They’re looking for things like: consistent use of high-pressure language, repeated selling patterns, headers that don’t match content, links that don’t match visible text.

We assess your content patterns for signals that modern filters watch for. Sometimes the problem is obvious (you’re using all-caps subject lines, or your copy has the feel of classic spam). Often it’s subtle (you’re using the same urgency pattern in every subject line, or your calls to action trigger filters in certain mailbox providers, or your links look suspicious to reputation algorithms).

These patterns compound across campaigns. A single email with slight red flags passes through. Fifty emails from the same sender all with the same pattern triggers filters.

System Interaction Problems

Sometimes the problem isn’t any single element, but how elements interact.

Your cold outreach has high complaint risk, which damages your domain reputation. That reputation damage affects your marketing email and transactional email. Your complaint rate is technically fine, but your unsubscribe rate is high, and high unsubscribe is an engagement signal that triggers filtering.

We look for these system-level interactions. A diagnostic often surfaces a primary problem (usually reputation or behavior related) that’s masking or compounding secondary problems. Fix the primary problem and the secondary problems sometimes resolve themselves.

Our Revenue Director, Chrisley Ceme, is leading the Triggered Outbound program.Chrisley’s gone deep on this strategy and can walk you through:

  • How Triggered Outbound fits with your outbound goals
  • What triggers are available (and what’s possible within our platform)
  • Pricing, onboarding, and getting started
Talk To Chrisley

Senders Case Studies

See All Case Studies

Momofuku

Founded by chef David Chang, Momofuku is a renowned culinary brand with a nation-wide presence, including restaurants and an online store with delicious goods. They ran into an issue with their email sending – high bounce rates and blocked sending. With hundreds of thousands of people on their email lists eager to stay informed, and an impeccable reputation to uphold, Momofuku wanted to nip this problem in the bud quickly.

  • Momofuku reached out to Senders to run a diagnostic test on their sending infrastructure and find the root cause
  • Senders deliverability experts discovered an issue with their DMARC, which was preventing emails from being sent, as their WordPress wasn't aligned with their SPF
  • Senders provided the most effective solution helping Momofuku restore safe sending, and suggested next steps to ensure everything keeps running smoothly on their end
  • The client reported that Senders helped identify the problem and got them back on track 

Andrew Yeung

Where many others see a problem, Andrew sees an opportunity. His work may center around product leadership at Google (and previously Meta), but his true calling is all about bringing brilliant change-makers together.

How it started: Andrew hosted small-scale dinners for a handful of people at the peak of the pandemic in NYC, to enable safe connections during the most isolating times. How it’s going: His events now count as many as 2,000 tech leaders each, and he has set up 100+ such parties for more than 15,000 people in the past couple of years. Andrew understands that if two minds are better than one, putting two thousand together, preferably in the same room, can make a profound difference.

Given the impact of his community-building efforts, people want him to be able to reach out – and email is often the best way to do so. So, we helped out a bit.

  • Andrew came across deliverability issues that prompted him to get in touch with Senders and look into the best possible solutions
  • The Senders team made the necessary domain configuration adjustments, with a focus on the domain’s email authentication settings to enhance security and deliverability
  • The SPF record was updated to include “Brevo” (Sendinblue) to strengthen authentication and reduce the chance of landing emails into spam
  • The DMARC policy update enabled better readability of DMARC reports for human analysts, which is essential for preventing email spoofing and phishing
  • Senders fixed the missing DKIM setup with Google, so that it now shows the email hasn’t been tampered with in transit
  • As a result, the client now has better, more stable email deliverability and security

Myrina.ai

Stands out as a trailblazer in empowering women entrepreneurs through technology and a supportive community.

Myrina.ai offers a cutting-edge range of AI-powered SaaS marketing and sales tools that cater specifically to female entrepreneurs and women-led businesses. Myrina.ai enables users to automate marketing and sales, while helping them scale their authentic selves while saving time and boosting conversions. Their Myrina’s Army community fosters a supportive platform that champions female entrepreneurs and their values, empowering them to conquer barriers and achieve their business goals. The company's dedication to providing not only top-notch technological solutions but also a platform for networking and mentorship underscores their commitment to fostering success among women in the entrepreneurial space.

Naturally, they wanted to make sure their email sending infrastructure was set up correctly to protect their reputation and successfully reach their recipients. Our deliverability team worked with the client’s team on:

  • Aligning the client’s three domains with Amazon to make sure they are compatible and optimized in order to integrate with Amazon’s system
  • Setting up a proper DMARC policy to protect their domains against unauthorized use and phishing scams
  • Enhancing email deliverability as well as security, so that each email sent from these domains can be properly authenticated and more likely to land in the right inbox
  • As a result, the client can protect the reputation of their business and domains, while safely sending out their email campaigns

Physician’s Choice

Sometimes the sheer number of options of any product can be daunting – how on earth do you pick the right one? This is especially true with supplements, as we can find them just about anywhere, but we can rarely understand a third of the ingredients listed. Unlike most, Physician’s Choice provides supplements with pure, potent ingredients that work. No fillers or “proprietary” blends with unidentified ingredients. They do the research, so you don’t have to.

  • The client’s team spotted issues with DMARC failures in Google Postmaster
  • The Senders deliverability team worked with the client to update the DMARC configuration to enable report collection
  • The client is now able to obtain detailed reports to diagnose the exact causes of the failures and prevent them in the future with proper DMARC setup