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My Open Rates Suddenly Dropped – What Happened?
Troubleshooting
Blog > Troubleshooting > My Open Rates Suddenly Dropped
By Nikita Bykadarov, CEO of Maildoso · Updated June 15, 2026 · 6 min read
My Open Rates Suddenly Dropped – What Happened?
Based on patterns we see across 400,000+ mailboxes and 10M+ emails sent per day on Maildoso infrastructure.
Short answer: A sudden open-rate drop is one of two things: your mail started landing in spam, or your open tracking broke. Rule out tracking first – check whether replies and clicks also fell. If they did, it's deliverability, and you fix it like a spam problem. If only opens fell, your tracking pixel or tracking domain is the culprit. Don't over-trust open rate either way; it's a noisy metric now.
Short answer: A sudden open-rate drop is one of two things: your mail started landing in spam, or your open tracking broke. Rule out tracking first – check whether replies and clicks also fell. If they did, it's deliverability, and you fix it like a spam problem. If only opens fell, your tracking pixel or tracking domain is the culprit. Don't over-trust open rate either way; it's a noisy metric now.
Key Takeaways
- An open-rate drop is either real (deliverability) or measured (broken tracking). Tell them apart before acting.
- If replies and clicks fell too, it's deliverability – treat it as a spam-placement problem.
- If only opens fell, suspect a blocked tracking pixel or a blacklisted tracking domain.
- Open rate is unreliable since Apple Mail Privacy Protection. Watch replies and positive replies as your real signal.
First: is the drop real or just measurement?
Open rate is the least trustworthy number in cold email, so don't panic at the chart before you confirm it reflects reality. The fastest check: look at your other metrics over the same window.
Replies and clicks also dropped?
The drop is real. Your mail is reaching fewer inboxes – treat it as a deliverability problem.
Only opens dropped, but replies held steady?
The drop is a measurement. Your tracking broke; your mail is still landing.
That single comparison tells you which half of this guide to read.
Replies and clicks also dropped?
The drop is real. Your mail is reaching fewer inboxes – treat it as a deliverability problem.
Only opens dropped, but replies held steady?
The drop is a measurement. Your tracking broke; your mail is still landing.
That single comparison tells you which half of this guide to read.
Why open tracking breaks (the "measurement" causes)
Open tracking works by loading a tiny invisible pixel. Anything that stops the pixel from loading shows up as a lower open rate even when nothing changed for the recipient.
Apple Mail Privacy Protection. Apple preloads images, which used to inflate opens. When sending mix or Apple behavior shifts, the inflated number corrects downward and looks like a drop.
Blocked or blacklisted tracking domain. If the custom tracking domain your sequencer uses gets flagged, the pixel and your links stop resolving – opens crater and deliverability suffers too.
Image blocking. More recipients and providers block images by default, so the pixel never fires.
Switched to plain-text sending. Plain-text emails often drop the tracking pixel entirely, which is good for deliverability but zeroes your open data.
Apple Mail Privacy Protection. Apple preloads images, which used to inflate opens. When sending mix or Apple behavior shifts, the inflated number corrects downward and looks like a drop.
Blocked or blacklisted tracking domain. If the custom tracking domain your sequencer uses gets flagged, the pixel and your links stop resolving – opens crater and deliverability suffers too.
Image blocking. More recipients and providers block images by default, so the pixel never fires.
Switched to plain-text sending. Plain-text emails often drop the tracking pixel entirely, which is good for deliverability but zeroes your open data.
If your email contains an open tracker, Google will display this warning to its users.
Why deliverability slips (the "real" causes)
If replies and clicks fell with opens, fewer people are seeing your mail.
The causes are the same ones that send email to spam:
The causes are the same ones that send email to spam:
- Volume ramped too fast on new or recovering mailboxes.
- Broken SPF, DKIM, or DMARC after a DNS change.
- A bad list batch that spiked bounces or spam complaints.
- Sending-domain or mailbox reputation decay from sustained cold volume.
- Sending from the wrong infrastructure – free Gmail or one Workspace tenant carrying all your outreach.
The fix, step by step
If it's a tracking problem
- Check your tracking domain. Confirm the custom tracking domain in your sequencer resolves and isn't on a blacklist. Replace it if it's flagged.
- Stop trusting the absolute number. Apple MPP makes open rate directional at best. Compare trends, not exact percentages.
- Consider turning open tracking off. Open pixels can hurt deliverability. Many strong senders track replies and clicks only, and send closer to plain text.
- Re-baseline. After a tracking change, set a new normal and judge future campaigns against it.
If it's a deliverability problem
For the full deliverability playbook, see My emails are landing in spam – how do I fix it?.
- Run a seed/placement test across Gmail, Outlook, and Yahoo to confirm where you're landing.
- Repair authentication – make SPF, DKIM, and DMARC pass on every sending domain.
- Cut volume and re-warm the affected mailboxes before resuming normal sending.
- Clean the list and quarantine any batch tied to the drop.
For the full deliverability playbook, see My emails are landing in spam – how do I fix it?.
How to stop chasing open-rate ghosts
Open rate stopped being a reliable health metric the day mailbox providers started preloading and blocking images. Build your monitoring around signals that still mean something:
Maildoso provisions mailboxes and domains with SPF, DKIM, and DMARC auto-configured and warmup built in, so the reputation drops that quietly tank open and reply rates don't get a foothold.
- Track replies and positive replies as your primary KPI. They can't be faked by a preloaded pixel.
- Use a clean, dedicated tracking domain if you track at all, and watch it for blacklisting.
- Run weekly seed tests so you catch real deliverability drops before they show up as lost replies.
- Send from infrastructure built for outbound – separate domains, automated authentication, warmup, volume spread across many mailboxes – so the deliverability half of this problem rarely happens.
Maildoso provisions mailboxes and domains with SPF, DKIM, and DMARC auto-configured and warmup built in, so the reputation drops that quietly tank open and reply rates don't get a foothold.
FAQ
- Q:Why did my open rate drop suddenly with no other changes?A:Either your tracking broke or your deliverability slipped. Check whether replies and clicks fell over the same period. If they did, it's deliverability; if only opens fell, it's a tracking issue like a blocked pixel or flagged tracking domain.
- Q:Is a low open rate a deliverability problem?A:Not always. Since Apple Mail Privacy Protection, opens are unreliable, so a low number can be pure measurement. Confirm with seed placement tests and reply data before assuming your mail is in spam.
- Q:Should I turn off open tracking?A:Often yes. Open pixels can hurt deliverability and the data is noisy. Many high-performing senders track only replies and clicks and send close to plain text.
- Q:Does Apple Mail Privacy Protection inflate or deflate open rates?A:It inflates them by preloading images, which marks emails as opened even when nobody read them. When your Apple share or their behavior shifts, that inflated number can correct downward and look like a drop.
- Q:What open rate should I expect for cold email?A:Treat any single number with suspicion because of MPP, but healthy cold campaigns often see opens in the 40-60% range when tracking works. Judge trends over time and lean on reply rate as the truer signal.
Key terms in this guide
Sources & references
About the author
Written by Nikita Bykadarov, CEO of Maildoso.
Nikita is founder and CEO of Maildoso, the cold email infrastructure platform powering 400,000+ mailboxes and 10M+ sends per day for 6,000+ companies. Because deliverability is his business, his team sees exactly why mail lands in spam and what brings it back – across thousands of domains and live campaigns. That's what informs the fixes here.
Last updated: June 2026.
- Open rate – the share of recipients recorded as opening an email, measured by a tracking pixel. Unreliable since image preloading and blocking became common.
- Tracking pixel – a tiny invisible image loaded when an email is opened; how opens get counted. If it doesn't load, the open isn't recorded.
- Tracking domain – the custom domain your sequencer uses for open and click tracking. If it's blacklisted, both your data and your deliverability suffer.
- Apple Mail Privacy Protection (MPP) – an Apple feature that preloads images, inflating recorded opens and making open rate a weak metric.
- Seed/placement test – sending to known inboxes across providers to see whether you land in primary, Promotions, or spam.
Sources & references
- Apple – Mail Privacy Protection overview
- Google – Email sender guidelines
- Google – Postmaster Tools
- Maildoso – Cold Email Deliverability Guide
About the author
Written by Nikita Bykadarov, CEO of Maildoso.
Nikita is founder and CEO of Maildoso, the cold email infrastructure platform powering 400,000+ mailboxes and 10M+ sends per day for 6,000+ companies. Because deliverability is his business, his team sees exactly why mail lands in spam and what brings it back – across thousands of domains and live campaigns. That's what informs the fixes here.
Last updated: June 2026.
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