How to Fix Email Deliverability Problems in Klaviyo

Email deliverability determines whether the rest of your email strategy gets a chance to work.

If inbox placement is weak, improving design or adding more campaigns will not solve the underlying problem.

A useful recovery framework covers four areas:

1. 1Technical authentication
2. 2List hygiene
3. 3Audience and reputation recovery
4. 4Email engagement

One clarification first, because it changes how brands read their own data. Landing in Gmail Promotions is not a deliverability failure. Promotions is an inbox category, not spam, and for many ecommerce brands it is exactly where commercial email belongs. Treating Primary placement as the only acceptable outcome leads brands to chase formatting tricks instead of fixing reputation.

No subject line style or plain-text template forces placement into a particular Gmail tab.

How to Diagnose a Deliverability Problem

Diagnosis means looking at several signals together, because no single metric proves inbox placement.

• bounce rate, and whether bounces are hard or soft;
• spam complaint rate;
• unsubscribe trends over time;
• open and click trends, read with privacy caveats in mind;
• performance broken down by inbox provider, since Gmail, Outlook and Yahoo can diverge sharply;
• inbox placement testing;
• blocklist and reputation signals where you can access them.

Seed and placement testing tools such as GlockApps can help you see where messages are landing rather than inferring it from engagement. They are one option among several, not a requirement.

Be careful with open rates specifically. Privacy protection features inflate some opens and hide others, so a falling open rate is a prompt to investigate rather than proof of a spam problem. There is no threshold below which spam placement is confirmed.

Step 1: Fix Authentication and Sending Setup

Authentication is where every deliverability repair should start, because nothing else compensates for it.

Confirm that you have:

A branded sending domain

Sending from your own domain rather than a shared platform domain, so reputation accrues to you.

SPF

Authorizes which servers may send on behalf of your domain.

DKIM

Cryptographically signs your messages so receivers can verify they were not altered.

DMARC

Tells receivers how to handle messages that fail authentication, and gives you reporting on what is being sent in your name.

A consistent From address and domain

Frequent changes to the sending identity reset the reputation you are trying to build.

BIMI is an optional brand identity layer that can display your logo in supporting inboxes. It is a trust and recognition feature built on top of DMARC enforcement. It is not required for deliverability and implementing it does not by itself improve inbox placement.

Step 2: Clean the List

Sending to addresses that cannot or will not engage is one of the fastest ways to damage reputation.

Suppress in this order of priority:

1. 1hard bounces, immediately and permanently;
2. 2repeat soft bounces across multiple sends;
3. 3anyone who has marked your email as spam;
4. 4clearly inactive never-buyers, after a genuine re-engagement attempt.

Avoid applying one universal rule such as deleting everyone inactive for 180 days. Purchase cycle and customer value both matter. A customer who buys a durable product once every two years is not inactive in the way a subscriber who never purchased and never opened is.

Treat existing customers differently from never-buyers. The reputational risk they carry is usually lower and their value is usually higher.

Step 3: Rebuild Sender Reputation Gradually

Reputation recovers by proving to inbox providers that people want your email, which means starting narrow and widening only while signals hold.

A workable framework:

1. 1send only to your most engaged recent subscribers;
2. 2widen to a broader recent-engagement audience;
3. 3extend to a 60-day engagement window;
4. 4extend to a 90-day engagement window;
5. 5broaden further only while bounce, complaint and placement signals remain healthy.

Do not lock this to a fixed weekly timeline. How fast you widen depends on how the signals respond, and a step backward is sometimes the correct next move.

This is much easier to run when you already have reliable engaged segments built and maintained.

Step 4: Improve Engagement

The strongest long-term deliverability protection is sending messages subscribers actually value.

In practice that means:

• campaign angles that offer something beyond another promotion;
• less repetitive discount messaging;
• clarity above the fold so the point lands in seconds;
• one obvious call to action;
• concise copy;
• the occasional personal or plain-text email;
• segmentation so fewer people receive irrelevant sends;
• offers that match where the customer actually is in the lifecycle.

Encouraging replies is sometimes described as a ranking hack. Treat it more carefully than that: genuine interaction is a reasonable relevance and engagement signal, but no one outside the inbox providers can confirm how specific interactions are weighted.

Content planning and deliverability are closely linked, which is why cadence and mix belong in the same conversation as your ecommerce email marketing calendar.

Sending Volume Consistency Matters

Mailbox providers respond to patterns, not just to individual sends. Two sending behaviors create avoidable risk.

Long inactivity followed by a large send

A brand that goes quiet for weeks and then mails its full list looks unfamiliar to providers at exactly the moment it needs to be trusted.

Sudden volume spikes

Peak-season sends to audiences you have not contacted recently can trigger filtering even when the list is technically clean.

Relatively steady sending to engaged audiences, with deliberate ramping before high-volume periods, is the safer pattern. Monitor placement signals per mailbox provider rather than as a single blended number, because problems often appear at one provider first. See how to clean your email list in Klaviyo and how to set up a branded sending domain in Klaviyo.

Deliverability Recovery Is Not a One-Time Project

Deliverability is a standing operational discipline, not a fix you apply once and forget.

Ongoing work includes:

• monitoring bounce, complaint and placement signals;
• protecting list growth quality at the signup form;
• maintaining suppression logic;
• keeping campaign targeting deliberate;
• keeping content genuinely worth opening;
• reviewing authentication when domains or platforms change;
• planning for seasonal volume spikes before they happen.