Klaviyo email deliverability issues concentrate around one pattern specific to how ecommerce brands use the platform: automated flows (welcome, abandoned cart, post-purchase, win-back) keep running indefinitely, and the share of flow recipients who are no longer engaged grows quietly over time.
Authentication first, regardless of the flow angle
Klaviyo's domain authentication screen issues SPF and DKIM values specific to your account - copy the exact DKIM selector and any dedicated sending subdomain from that screen at setup time rather than assuming a standard value. Verify propagation directly:
dig TXT yourdomain.com +short dig TXT _dmarc.yourdomain.com +short
A domain with SPF configured but DKIM still showing "unverified" in Klaviyo's dashboard is authenticating only partially, which several major mailbox providers now treat as insufficient on its own for bulk senders.
Flow-level engagement decay is the ecommerce-specific risk
| Flow type | Why engagement decays | What to check |
|---|---|---|
| Welcome series | Fine initially, but non-buyers who never engage stay in flow logic indefinitely if not gated | Exit non-engagers after 2-3 unopened emails |
| Abandoned cart | High initial relevance, but repeat non-converters accumulate | Cap retries, suppress after no engagement across several attempts |
| Post-purchase | Strong short-term engagement, decays over months as buyers move on | Suppress from marketing flows after 6+ months of no opens |
| Win-back / sunset | Targets cold contacts by design | Separate subdomain, conservative volume, close monitoring |
Because flows run on autopilot, this decay is easy to miss - nobody manually decided to keep emailing a non-engaged segment, the flow logic just never stopped.
Segment by engagement before increasing send frequency
If you're considering increasing flow frequency or adding new automations, check current engagement segmentation first. A domain sending to a largely disengaged audience will see placement degrade faster as volume increases, regardless of how well-authenticated the domain is.
What Klaviyo's reporting does and doesn't show
Klaviyo's flow and campaign reports show opens, clicks, and revenue attribution - useful business metrics, not deliverability metrics. Apple Mail Privacy Protection inflates opens for a meaningful share of Apple Mail recipients regardless of actual engagement, and a delivered-but-filtered message (landing in spam or Promotions) still reports as delivered, because the SMTP transaction succeeded. Seeing actual placement requires a seed-inbox test across Gmail, Outlook, and Yahoo.
List growth source still matters most
A list built through confirmed opt-in on your storefront behaves very differently from one grown through a popup with no confirmation, co-registration, or an imported list from another channel. If deliverability is degrading alongside rapid list growth, check acquisition source before assuming the issue is flow logic or authentication.
Comparing new vs. established flows
A brand-new flow built on a domain with solid existing reputation will generally ramp faster than the same flow built on a brand-new domain, since domain-level reputation carries across flows. But a new flow targeting a meaningfully different audience segment than your existing flows - a win-back flow versus a post-purchase flow, for instance - can still underperform relative to expectations if that segment's actual engagement doesn't match the assumptions the flow was designed around. Watch early engagement data closely in the first few weeks of any new flow rather than assuming it will perform like your established ones.
Checking placement independent of flow performance
Because flow metrics and revenue attribution are the primary signals most Klaviyo users watch, it is worth deliberately checking placement independent of that reporting on a regular basis. A seed-inbox test run monthly, or after any significant flow change, catches placement problems that revenue numbers alone will not surface - a flow can still generate orders from the recipients who do reach the inbox while a growing share of sends quietly fail to arrive at all.
What not to do
Do not let a win-back or sunset flow run against the same sending domain as your core transactional and high-engagement marketing mail without considering isolation. A win-back flow is, by design, targeting cold contacts - if it damages domain reputation, isolating it to its own subdomain keeps that damage from reaching order confirmations and your best-converting flows.
Do not assume flow revenue attribution tells you anything about deliverability. A flow can be profitable on the emails that do land in the inbox while a growing share silently lands in spam - revenue and placement are not the same measurement.
Where MailPilot fits
MailPilot does not integrate with Klaviyo. For the sending domain or mailbox behind your Klaviyo flows, if reachable over OAuth (Gmail, Outlook) or SMTP/IMAP (SendGrid, Amazon SES, Mailgun, Postmark, custom SMTP), MailPilot checks SPF/DKIM/DMARC against live DNS, runs seed-inbox placement tests, and tracks daily reputation per mailbox - specifically useful for catching the flow-level engagement decay described above before it reaches transactional mail.
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