Some portion of the candidates you think ghosted you never saw the email. "Delivered" means the receiving server accepted the message, not that a human ever laid eyes on it; one agency-side audit of 40 recruiting firms claimed 30 to 50 percent of sends from broken email setups land in spam, invisibly. Practitioner threads on r/RecruitmentAgencies tell the same story from the inside: solo recruiters burning fresh domains in their first month and asking whether they are, quote, screwed.
Deliverability used to be a dark art recruiters could ignore because one-to-one email from a real work address mostly just arrived. Between February 2024 and November 2025, the major inbox providers rewrote that deal. Here is what changed, and the setup that keeps a recruiting desk out of the spam folder in 2026.
What Gmail and Outlook actually changed
Three dates matter. In February 2024, Google and Yahoo began enforcing sender requirements for any domain sending 5,000 or more messages a day to their users: SPF and DKIM authentication, a DMARC policy, a spam-complaint rate kept below 0.3% (with 0.1% as the stated target), and RFC 8058 one-click unsubscribe headers on marketing mail. In May 2025, Microsoft applied the same core requirements to high-volume senders reaching Outlook, Hotmail, and Live addresses. And starting November 2025, Gmail escalated from filtering to rejection: non-compliant traffic now bounces instead of quietly rotting in spam.
Where inbox placement actually stands in 2026
The post-enforcement numbers explain why this stopped being optional. Across 15 major email service providers, average inbox placement in EmailToolTester's 2026 benchmark is 83.1%: roughly one in six legitimate emails never reaches the inbox at all. The provider split matters for recruiters specifically: Gmail places 87.2% of mail, while Microsoft Outlook sits at 75.6%, which is why practitioner threads single out Outlook-heavy client lists as the place sequences quietly die. On the outcome side, Instantly's 2026 benchmark report, built on billions of sends, puts the average cold email reply rate at 3.43% (top decile: 10.7%+) and recommends treating 80% inbox placement as the working floor. If your reply rates sit far below those numbers, assume placement, not copy, until proven otherwise.
"But I don't send 5,000 emails a day." Correct, and it does not save you. The thresholds define who Google will formally classify as a bulk sender; the filtering machinery behind the rules (authentication checks, domain reputation, complaint tracking) runs on every message from every domain. An unauthenticated recruiting domain in 2026 is not exempt, it is just small enough that nobody warns you before the filters act. The rules are the clearest public statement of what inbox providers now consider normal email hygiene, and small senders get judged by the same signals with less data to average out one bad day.
The recruiter's deliverability checklist
Work through these in order. The first three are one-time DNS records your domain host or IT admin can set in an afternoon; the rest are habits.
| Step | What it does | Recruiter-specific note |
|---|---|---|
| 1. SPF record | Lists the servers allowed to send mail for your domain | Must include every tool that sends as you: your mailbox provider, your ATS, your sequencing tool |
| 2. DKIM signing | Cryptographically proves the message wasn't altered and came from your domain | Enable it in each sending tool separately; an unsigned sequence tool undermines a signed mailbox |
| 3. DMARC policy | Tells inboxes what to do when SPF/DKIM fail, and sends you reports | Start at p=none to monitor, move to quarantine once reports look clean. p=none satisfies the 2025 Outlook baseline |
| 4. Warm new domains slowly | Builds sending reputation gradually | A new agency domain has no history; weeks of low-volume, real, replied-to conversations before any sequence. Rushing this is the #1 solo-agency mistake |
| 5. List hygiene | Keeps bounce and complaint rates down | Dead addresses are the silent killer: every bounce tells the provider you don't know your recipients. Verify addresses before sending, not after |
| 6. Monitor | Shows your actual spam rate and reputation | Google Postmaster Tools is free and takes ten minutes to set up. Below 0.1% complaints is the target; 0.3% is the cliff |
Two structural decisions deserve more than a table row.
Main domain or subdomain? Send one-to-one candidate email from your primary domain (a real person, a real address, maximum trust), and run sequences from a dedicated subdomain like mail.youragency.com. The subdomain carries its own reputation, so an aggressive campaign week cannot poison the domain your client emails come from. What you should not do is buy a lookalike domain (youragency-talent.com); those pattern-match to phishing infrastructure.
Volume discipline beats volume tools. Recruiting outreach sits in an awkward middle: it is one-to-one in content but campaign-like in mechanics. The closer your sending behavior looks to a person writing to another person (modest daily volume, personalized first lines, replies that continue threads), the more the machinery works in your favor. Blasting 300 identical messages a day from a two-month-old domain looks like exactly what it is.
Deliverability cannot fix a targeting problem
Getting into the inbox is necessary and insufficient. If the message that arrives is irrelevant, the recipient's delete (or worse, spam report) feeds the same reputation system you just repaired, and spam complaints from annoyed recipients are the one metric with a hard numeric cliff. The 0.3% threshold means three complaints per thousand sends; a poorly targeted sequence gets there in a week.
So the deliverability fix and the targeting fix are the same project. Fewer, better-chosen recipients lower complaint rates, raise replies, and build the engagement history that providers read as legitimacy. That starts with contact data that is current (verified emails, not scraped lists full of dead addresses) and with candidates who have some behavioral likelihood of wanting the message: the logic behind Glozo's Open to Offers signal and pay-per-reveal contact model, where you reveal a verified address for a candidate worth contacting instead of importing a stale thousand-row CSV. The copy layer comes after; why outreach gets ignored and our email templates that get replies cover it.
When email reputation is damaged and you need a channel while it heals, remember the sequence problem is multichannel anyway: InMail economics make it a poor primary channel but a workable fallback, and Glozo Outreach runs email and LinkedIn steps in one sequence so a spam-folder week does not zero your pipeline.
If you are starting an agency domain this month
The compressed version for a new solo desk. Register the domain and set up SPF, DKIM, and DMARC (p=none) before sending anything. Spend the first several weeks using the address like a human: correspondence with clients, candidates you already know, peers, with real replies. Add Postmaster Tools in week one so you have baseline data. Only then introduce sequences, starting at low daily volumes from a subdomain and scaling only while complaint and bounce rates stay near zero. The Reddit graveyard of burned agency domains is mostly people who ran this list in reverse.