Hey it’s Idris from Retentiononly.
Here's a number that should bother you.
21% of legitimate marketing emails from real businesses never reach the inbox.
Not because the copy is bad. Not because the offer is wrong. Because spam filters silently killed them before anyone had the chance to read them.
We've audited Klaviyo accounts across 7, 8 and 9-figure D2C brands, brands with full agencies, in-house teams, the works.
Nearly all of them had a deliverability problem they didn't know about.
Here are the exact reasons it happens and what to fix, right now.
Prefer to watch instead of read? Full breakdown here: https://youtu.be/q--61V3AWtw
Fix #1: Your email content is triggering filters
Spam filters scan every word of your subject line and email body.
Classic triggers: ALL CAPS, multiple exclamation points!!!, phrases like "free money" or "act now." If you're using any of these, stop immediately.
But it goes deeper than buzzwords.
Image-to-text ratio — emails that are one giant image with barely any text are a red flag. Include at least 200–300 characters of actual written text in every email.
Messy HTML — copying from Word or using poorly coded templates leaves hidden formatting that filters flag as suspicious.
Missing footer info — every email needs a physical address and an unsubscribe link. No exceptions. Missing either is an automatic spam signal.
What to do: Clean professional subject lines, real text in every email, and a complete footer. Every time.
Fix #2: Authenticate your domain (SPF, DKIM, DMARC)
This is the technical one, but it's non-negotiable.
As of February 2024, Gmail and Yahoo require all bulk senders to have SPF, DKIM and DMARC set up. Without them, your emails go straight to spam by default.
SPF — tells email providers which servers are allowed to send on your behalf
DKIM — adds a digital signature proving your email hasn't been tampered with
DMARC — ties both together and tells providers what to do if authentication fails
The good news: Klaviyo and Mailchimp make this straightforward to set up. You just need to add the DNS records and use a branded sending domain (e.g. [email protected] — not [email protected]).
What to do: Use a free SPF and DMARC checker to confirm yours are set up correctly.
Fix #3: Your sender reputation is quietly tanking
Think of your sender reputation like a credit score. Built slowly. Destroyed fast.
Here's what damages it:
High bounce rate — keep it below 1%. In Klaviyo, exclude anyone who has bounced 3+ times in the last 180 days.
Spam complaints — keep them under 0.1%. One bad batch can set you back months.
High unsubscribe rate — target below 0.3%. Use Smart Sending to avoid hitting the same person twice in 16 hours.
And if you're on a shared IP (most brands are), you're tied to every other sender on that infrastructure. One bad actor can hurt your deliverability even if you've done nothing wrong.
What to do: For brands at scale, consider moving to a dedicated IP. You control your own reputation entirely.
Fix #4: You're emailing people who don't want your emails
This is the big one.
Gmail watches what the first batch of recipients does with your email, do they open it, click it, delete it, or mark it as spam? Based on that signal, it decides whether to deliver the rest of your campaign to inboxes or spam folders.
If you keep emailing disengaged subscribers, your engagement tanks. And when engagement tanks, deliverability tanks with it.
What to do: Build an engaged segment in Klaviyo. Aim for a 35–40% open rate. That's the threshold that keeps you in the best shared IP pool and out of the spam bucket.
Fix #5: Segment. Don't blast.
Sending every email to your entire list is one of the fastest ways to destroy your deliverability.
Different subscribers have different levels of engagement, different purchase histories, and different interests. Treating them all the same means most of them will eventually stop opening and that kills your sender score.
What to do: Segment by engagement level, purchase behaviour and interests. Give subscribers the option to choose their own frequency in the footer, it's better than losing them to an unsubscribe entirely.
Fix #6: Test before you send
Most brands find out they have a deliverability problem after the damage is done.
Tools like Mail Tester and Email on Acid let you preview issues before a campaign goes out. Run a test. See exactly where you'd land — inbox, spam, or promotions tab — across different providers.
What to do: Test every campaign before sending. It takes 5 minutes and can save thousands.
Fix #7: Monitor what Gmail is actually telling you
Klaviyo gives you open rates. That's useful. But it doesn't show you what Gmail sees.
Google Postmaster Tools does. It shows your domain reputation, spam rate and deliverability performance specifically inside Gmail, the inbox provider that matters most.
What to do: Set up Google Postmaster Tools and check it regularly. It's free and it's the most honest feedback you'll get.
Here's the reality
Most brands assume their emails are being delivered. They're not checking. They're just watching open rates and wondering why revenue feels flat.
Fixing your deliverability doesn't require a bigger list or more spend. It requires knowing what's broken and fixing it systematically.
If your brand is doing at least $100K/month and you want us to audit your email setup deliverability, segmentation, campaigns and tell you exactly what's costing you revenue:
Book your free audit here: https://calendly.com/idris-farjad/free-audit-english-website
Or if you want the full breakdown with every tool, checklist and example shown on screen:
Watch the video here: https://youtu.be/q--61V3AWtw
Speak soon,
Idris