You open Lemlist on Monday. Your open rate chart looks like a cliff. Replies have stopped. The sequence that was getting 44% open two weeks ago is now at 9%. Nothing changed on your end — no new template, no list import, no DNS edit.
After running hundreds of placement tests on Lemlist accounts, we can tell you the answer is almost always one of exactly four things. Here is how to find out which, and fix it.
The four causes
- DNS change. Someone edited your SPF, DKIM or DMARC record — or a registrar auto-renewed and wiped a TXT record. Authentication is now failing or misaligned, and Gmail has moved you to Spam.
- Warm-up paused. Lemwarm or your third-party warm-up stopped (billing lapse, account disconnect) and your inbox lost the reputation-supporting engagement loop.
- Shared tracking domain blocklisted. Lemlist's default click-tracking goes through
email.lemlist.comand similar shared hostnames. If one ends up on URIBL, every Lemlist account using that host suffers simultaneously. - Sequence-pattern flag. You (or enough other Lemlist users) are sending the same subject line and near-identical opening lines at scale. Gmail's pattern-matching classifier flags the whole template family.
Lemlist users default to blaming list quality when placement drops. Cold-outreach lists are often stale, but that causes a slow decline over weeks. A sharp overnight drop — the common pattern — is always one of the four causes above.
Running a free placement test to narrow it down
Send one step of your live sequence to a seedbox list. In 60 seconds you get four answers at once:
- Auth verdict — SPF/DKIM/DMARC pass or fail, with alignment. Tells you if cause #1 applies.
- Per-provider placement — Gmail, Outlook, Yahoo etc. If Gmail has collapsed but Outlook is fine, your domain reputation is OK and something Gmail-specific (tracking domain, content pattern) is the issue.
- Content scores — SpamAssassin and Rspamd verdicts. A score above 5 points at a content or pattern issue.
- Blocklist check — tracking domain, sending IP, recipient domain on the common DNSBLs.
Cause #1: DNS change — how to fix
Look at the Authentication-Results header of the test message. You are looking for three pass-es:
spf=pass, dkim=pass with d=yourdomain.com, dmarc=pass.
If any of the three fails, go back into your DNS and reconcile with Lemlist's DNS setup page. The most common Lemlist-specific failure: the dedicated sending subdomain (often send.yourdomain.com) lost its include: entry during a registrar migration. Add it back, wait an hour for cache, rerun the test.
Cause #2: Warm-up paused — re-warming a cold account
Warm-up pauses are the single most common cause of placement drops among agency-managed Lemlist accounts. A credit card bounces, a Lemwarm connection breaks, a user turns it off for "just a day" — and two weeks later placement is underwater.
Re-warming protocol:
- Reconnect Lemwarm (or switch to Warmy / Mailreach / Warmup Inbox).
- Pause all cold campaigns for 10 days. Warm-up alone, no outbound send.
- On day 11 resume outbound at 50% of previous volume. Ramp back to full over 5 days.
- Re-test placement at day 5 and day 15 of the ramp. You are looking for Gmail Inbox >70% before you push further.
Cause #3: Shared tracking domain blacklisted
Check your Lemlist account's tracking domain setting. If you're using the default Lemlist-shared tracking host (common for new accounts), look up that host on URIBL / SURBL / Spamhaus DBL.
Fix: switch to a custom tracking domain on a CNAME under your own sending domain, e.g. track.yourdomain.com. Lemlist supports this in Sender settings → Tracking domain. Use a subdomain that is at least 30 days old — a brand-new subdomain has zero reputation and can perform worse than the shared default.
In our aggregate data, Lemlist accounts that move from the shared default tracking host to a properly authenticated custom tracking subdomain gain an average of 14 percentage points on Gmail Inbox. It is the highest-leverage fix available.
Cause #4: Sequence-pattern flag — rotating subject lines
If your sequence uses a single subject line across thousands of sends, Gmail's classifier learns it as a fingerprint. Add variations — Lemlist's spintax feature is the right tool here.
Practical approach:
- Use at least 5 subject-line variants via spintax. Vary by noun (
{meeting|call|intro}) and by phrasing ({Quick question about|Thoughts on}). - Rotate opening sentences in step 1. The first 120 characters of the body are what the classifier fingerprints hardest.
- Drop obvious cold-email tells: "Hope this finds you well", "I was looking at your website", "noticed you're hiring".
- Move step 2 onward to a different subject thread rather than
Re:. Lemlist's default reply-chain threading is a known pattern to Gmail.
Lemwarm vs external warm-up
Lemwarm is convenient — same dashboard, same billing — and it works. External tools (Warmy, Mailreach, Warmup Inbox) send through more providers and typically produce slightly higher Gmail Inbox numbers in side-by-side tests. For a primary sending inbox we recommend a dedicated external warm-up tool and use Lemwarm as a secondary signal.
Whichever you use: it must run continuously. Warm-up pauses are worse than never starting, because the model notices the shift.
GlockApps vs Inbox Check for Lemlist users
GlockApps runs scheduled placement tests and tracks blocklists over time. For an agency managing ten Lemlist accounts, the automation is genuinely useful — expect to pay $79–$399/month depending on volume. For a single Lemlist account trying to diagnose a live placement drop, the free flow above gets you the same answer in ten minutes. Inbox Check covers the 20+ seedbox providers, SPF/DKIM/ DMARC verdicts, SpamAssassin and Rspamd scores, and blocklist lookups — at no cost.