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Why Are My Emails Going to Spam?
Legitimate email usually lands in spam for one of seven reasons, and almost all of them trace back to two things mailbox providers actually measure: can they prove you are who you say you are, and do people want your mail. The most common culprit is broken authentication, which since February 2024 quietly fails bulk senders at Gmail and Yahoo. Close behind are list problems, low engagement, spam-trigger content, volume spikes with no warm-up, a broken unsubscribe, and the occasional blocklisting. Every one is diagnosable in a few minutes. This is the troubleshooting companion to our email deliverability guide.
How to read this. The causes are ranked by how often they are the real problem, most common first. Work top-down, fix what applies, and re-test. Resist changing five things at once, or you will not know what worked.
1. Authentication failures (SPF, DKIM, DMARC)
This is the number-one reason real email gets junked, and since February 1, 2024 it is also the fastest way to get bulk mail rejected outright. Google and Yahoo now require anyone sending more than 5,000 messages a day to a Gmail or Yahoo address to authenticate with SPF, DKIM, and DMARC, with the From domain aligned to one of them. Miss any of the three and your mail gets filtered or bounced regardless of how good the content is.
SPF says which servers are allowed to send for your domain.
DKIM cryptographically signs each message so the recipient can verify it was not tampered with.
DMARC tells mailbox providers what to do when SPF or DKIM fails, and gives you reporting.
The fix. Set up all three on a sending domain you control. Loops signs every outgoing message with DKIM from your first send, gives you a ready-to-copy default DMARC record, and publishes its SPF record at a dedicated subdomain (envelope.sendingdomain.com) so it will not collide with an existing SPF record on your root domain. Add the records at your DNS provider, then click Verify Records. Start DMARC at p=none, confirm your legitimate mail is passing, then tighten to quarantine and eventually reject. See the DMARC & DKIM setup guide. Give DNS changes up to 24 hours to propagate before re-testing.
2. Poor list quality, no consent, or purchased lists
Mailbox providers are very good at spotting mail nobody asked for. If you bought a list, scraped addresses, or pre-checked an opt-in box, you will see spam placement, hard bounces, and complaints fast, and those complaints poison your reputation for the recipients who did opt in. A single bad import can move your whole domain to spam.
The fix. Only email people who explicitly opted in. Never buy or rent a list. Stop disposable and role addresses at the door, and re-confirm intent for anyone you are unsure about. In Loops, turn on double opt-in so new signups confirm before they receive marketing mail, and use the email blocklist to keep known-bad addresses out. If a chunk of your list has gone cold, prune it. Maintaining a clean list is one of the biggest deliverability levers you have.
3. Spam-trigger content and formatting
Content rarely sinks an authenticated, well-liked sender on its own, but it absolutely tips a borderline message into spam. Filters score the whole package: text-to-image ratio, link quality, code hygiene, and subject-line patterns.
All-image emails with little real text read like the image-only spam filters were trained on. Keep a healthy text-to-image balance.
Sketchy or mismatched links hurt. Loops’ own investigation found shortened YouTube (youtu.be) links wrapped in click tracking landing in Gmail spam with a warning, while the full URL with the same tracking reached the inbox. The double-wrapping was the trigger. Avoid stacking URL shorteners and redirects.
Spammy subject lines and bodies (ALL CAPS, excessive punctuation) and regulated-industry content like crypto, gambling, or financial windfalls raise your score even when you are legitimate.
The fix. Write like a person, not a billboard. Balance text and images, link to full canonical URLs over shorteners, send yourself a test, and check the spam score before a big send. Loops runs content checks during sending and tests its own rendering against rspamd, the same open-source filter many recipients run, so platform-level encoding problems are handled before they reach a filter.
4. Low engagement and poor sender reputation
Gmail and the others watch what people do with your mail. Low opens, lots of delete-without-reading, and especially spam-button presses tell them your mail is unwanted, and they start routing it to spam preemptively. Reputation attaches to both your domain and your sending IP, built on engagement, consistency, and content quality over time.
The fix. Send relevant mail to engaged people on a steady cadence. Welcome new subscribers immediately with an automated workflow while intent is highest, then keep a consistent rhythm rather than going dark for months and blasting. Suppress or sunset chronically disengaged contacts. Watch your numbers in Google Postmaster Tools and keep your spam-complaint rate well under the 0.1% danger line (0.3% is the failure threshold).
5. Blocklists
If your domain or sending IP lands on a public blocklist (Spamhaus and friends), receivers that consult that list will junk or reject your mail wholesale. This usually follows from one of the problems above, a spam-trap hit, a complaint spike, or a compromised account, but it shows up as a sudden, across-the-board deliverability cliff.
The fix. Check your domain and IP against the major blocklists with a tool like MXToolbox. If you are listed, fix the underlying cause first, then follow each blocklist’s delisting process. On managed infrastructure like Loops, IP reputation and delisting are handled for you; your job is to not generate the complaints and traps that get a shared IP flagged.
6. Broken or missing unsubscribe
Counterintuitive but real: making it hard to leave sends more of your mail to spam. When people cannot find the unsubscribe link, they hit the spam button instead, the single most damaging signal you can generate. Since February 2024, Gmail and Yahoo also require bulk senders to support one-click unsubscribe (RFC 8058 List-Unsubscribe headers) and to honor requests within two days.
The fix. Put an obvious unsubscribe link in every marketing email and process opt-outs immediately. Loops automatically handles bounces, unsubscribes, and spam complaints for you, so opt-outs are honored and suppressed without manual work. A frictionless unsubscribe is cheaper than a complaint every time.
7. Sudden volume spikes and no warming
A domain or IP with little sending history that suddenly fires tens of thousands of messages looks exactly like a hijacked account, so receivers throttle or junk the surge. The same thing happens right after you move to a new domain or IP, which resets the reputation you had built.
The fix. Ramp gradually. New senders should start on a subdomain, keep early volume conservative, and grow steadily so engagement data accrues before the big campaigns. Keep a consistent cadence rather than long silences punctuated by blasts. If you are migrating domains, plan for a reputation reset and ramp again.
Diagnose it in 5 minutes
Run these in order. The first one that fails is very likely your problem.
Send a test to a Gmail and a Yahoo address. Inbox or spam? If spam, note any warning banner, the wording is a real clue.
Check authentication. Open the test, choose Show Original in Gmail. SPF, DKIM, and DMARC should all read PASS. Any FAIL or none is your top suspect (cause 1).
Check your spam-complaint rate in Google Postmaster Tools. Above 0.1% is the danger zone; 0.3% is failure.
Check your bounce rate. Under 2% is healthy; over 5% means a list-quality problem (cause 2).
Scan blocklists with MXToolbox for your domain and sending IP (cause 5).
Eyeball the email. Heavy on images, light on text? Shortened or redirected links? An unsubscribe link you can actually find? (causes 3 and 6).
Look at recent volume. Did sends spike, or did you just change domains? (cause 7).
How Loops prevents most of this by default
A lot of the list above is infrastructure work you should not have to think about. On Loops it is handled:
Authentication is guided and partly automatic. DKIM signs every message from your first send. Loops hands you ready-to-copy SPF, DKIM, and DMARC records and a Verify Records button, so you can pass the 2024 Gmail/Yahoo requirements without hand-rolling DNS.
Bounces, complaints, and unsubscribes are handled automatically. Hard bounces and complaints are suppressed for you, and opt-outs are honored, removing the dead weight that wrecks reputation.
Content is filtered before it ships. Loops monitors content during sending, tests its rendering against rspamd, and the Guardian system warns you about known triggers like double-wrapped shortened links before you send.
List quality has guardrails. Built-in double opt-in and an email blocklist keep junk and unconsented addresses off your list in the first place.
Managed reputation. IP reputation, bounce handling, and delisting are Loops’ problem, not yours.
Frequently asked questions
Why are my emails going to spam all of a sudden?
How do I stop my emails from going to spam?
Do I really need SPF, DKIM, and DMARC?
Does Loops set up SPF, DKIM, and DMARC for me?
What spam-complaint rate is too high?
Can the content of my email send it to spam?
Will buying an email list hurt deliverability?
How long until my deliverability recovers after a problem?
What Loops cannot do for you: get genuine consent, write relevant mail, and not blast a cold list. Those stay on your side. Start on the free tier or read the full deliverability documentation.