Why Are My Emails Going to Spam in Gmail? A Diagnostic Checklist

A prospect finally replies with "found this in my spam folder," and now you're wondering how many others never saw your email at all. Most advice at this point is a list of thirty tips in no particular order. That's not much help when you need to find the one thing that's wrong.

Emails usually go to spam for one of five reasons, roughly in this order of likelihood: failed authentication (SPF, DKIM, DMARC), a sudden jump in sending volume, links or content that look risky, a list of people who didn't expect to hear from you, and recipients reporting you as spam. This checklist takes them in that order, tells you how to check each one in a few minutes, and what to change. It also answers a question tracking companies rarely address: what tracking pixels and tracked links do to your deliverability.

Why are my emails going to spam? The short version

Start at the top. Authentication problems are the easiest to confirm and the most common reason a whole domain's mail lands in spam at once.

Step 1: Confirm where your email is landing

Before you change anything, find out how widespread the problem is. One person's spam folder tells you little. A pattern tells you where to look.

Send the same email, unchanged, to a few addresses you control: a personal Gmail account, an Outlook.com account, and if you can, a work address on a different provider. Then look at where each copy lands.

• Spam everywhere: the problem is probably on your side, usually authentication or your domain's reputation. Go to Step 2.
• Spam at Gmail only: Gmail's filters are reacting to something specific. Sending pattern and recipient complaints (Steps 3 and 6) are the usual suspects.
• Spam for one recipient only: that person's own filters, a corporate security gateway, or a rule they set up. Ask them to mark it as "Not spam" and move on.

If a copy lands in Gmail's spam folder, open it. Gmail usually shows a short banner at the top explaining why, such as "This message is similar to messages that were identified as spam in the past." That one line often points straight at the cause.

Step 2: Check SPF, DKIM, and DMARC with "Show original"

Every email carries a record of whether it passed authentication. You can read it in about 30 seconds. Google's help page on checking whether a message is authenticated describes the steps:

1. Open a message you sent, from the recipient's side (one of your test inboxes).
2. Click the three-dot More menu next to Reply and choose Show original.
3. Read the summary at the top, or search the raw headers for Authentication-Results.

You're looking for three results:

The last row is the one people miss. A message can pass SPF and DKIM and still fail DMARC, because the domain that passed isn't the one in your From line. This is common when a tool sends "as" you@yourcompany.com through its own servers.

Google's email sender guidelines require SPF or DKIM for everyone, and SPF, DKIM, and DMARC for bulk senders. Unauthenticated mail may go to spam or be rejected outright with a 5.7.26 error.

For Google Workspace on your own domain, the usual gaps are DKIM never being turned on in the Admin console, and an SPF record that lists an old provider but not Google. Maildriply's dashboard has a DNS check under Settings that looks up your domain's SPF, DKIM (with the google selector by default), and DMARC records and flags what's missing.

There's a second half to alignment that tools get wrong. Maildriply refuses to send a dashboard email if its From address isn't the Gmail account you connected. That rule exists for exactly this reason: Gmail sends and authenticates the message as the connected account, so a different From address would fail DMARC alignment. We have more on how API sending and SMTP relays differ in Gmail API vs. SMTP for cold email.

Step 3: Look at your sending pattern

If authentication passes and you're still in spam, look at how you've been sending, not what. Google's list of the top Gmail sender issues calls out increasing volume too quickly and sending inconsistent volumes, especially from new domains.

The classic pattern: an account that sends 10 emails a week starts sending 200 on Monday morning. Every one of those emails can be well written and authenticated. The jump is what stands out.

Questions to ask yourself:

• Did you start a campaign in the last week or two?
• Do your sends go out in one burst, or spread across the day?
• Is this a new domain or a new Workspace account?

If the answer to any of these is yes, slow down. Spread sends across working hours, build volume over a couple of weeks, and stay well under Gmail's sending limits, which are a ceiling, not a target. Maildriply paces dashboard campaigns this way by default: a newly connected account starts with a low daily cap that rises over its first couple of weeks of sending, and anything past the day's cap waits for the next day.

Step 4: Check your content and link domains

Spam filters care less about individual "spammy words" than older guides suggest. They care more about anything that looks misleading. Google's sender guidelines name specific things to avoid:

• Fake reply or forward subjects. "Re:" or "Fwd:" on a message that isn't a reply or forward.
• Hidden content. Text hidden with HTML or CSS, a common trick in spam.
• Links that hide where they go. Google asks for links that are "visible and easy to understand," so recipients know what to expect when they click.
• Impersonation. Display names or addresses that look like another company's.

Links deserve the most attention, because filters judge the domains inside your email, not just the domain you send from. Gmail's SMTP error reference includes a specific rejection for when Gmail sees an unusual rate of unsolicited mail containing one of your URL domains. A link shortener, or a domain that also appears in other people's spam, can drag your message down even when everything else is clean.

Practical checks:

• List every domain your email links to, including image hosts and anything in your signature.
• Look each one up on Google's Safe Browsing site status page. A domain flagged there is a problem in every email it appears in.
• Replace shortened links with the full URL.
• Send a stripped-down copy (plain text, no links, no images) to your test inbox. If it reaches the inbox and the full version doesn't, the problem is in the content.

Do tracking pixels and tracked links send emails to spam?

This is a fair question to put to any email tracking company, including us.

A tracking pixel on its own rarely decides whether an email lands in spam. It's one small remote image, and plenty of legitimate email (newsletters, receipts, sales email) carries one. Google's sender guidelines don't name tracking pixels as a cause. If your email is in spam everywhere, a pixel is not the first thing to suspect.

Tracked links matter more, for the reason in Step 4. To track clicks, a tool replaces each link with one on its own domain, which redirects to your original URL. Filters now see the tracking domain in your email, and Google's sender issues page warns that sharing domains with other senders means sharing their reputation. If a tracker's link domain is used by people who send spam, every customer's email carries that domain.

Here's how that works for us, so you can judge it yourself. When Maildriply tracks an email, the pixel and the tracked links point at our tracking domain, t.maildriply.com, and every customer shares it. Each tracked link is one redirect that only goes to the URL fixed when you wrote the email, so the domain can't be used as an open redirect for someone else's links. We don't add a logo, signature, or "sent with" footer to your mail. And because we send through the Gmail API from your own account, the message is authenticated as you, not as us.

Open tracking is also a poor way to detect spam placement. Opens are approximate (privacy proxies, scanners, and image blocking all distort them, as we cover in tracking pixels vs. link tracking). A run of zero opens from Gmail recipients is a hint that something is wrong, not proof that you're in spam.

Step 5: Clean your list

Sending to addresses that bounce, or to people who never expected your email, damages your reputation with every send. Google's top-issues page asks senders to get explicit permission and to honor unsubscribes.

• Bounces. If you're getting "Address not found" messages from Mail Delivery Subsystem, remove those addresses now. Too many bounces in a short time can also get your account temporarily blocked from sending.
• Bought or scraped lists. These are full of dead addresses and people who will report you. Don't use them.
• Old contacts. Someone you emailed three years ago may not remember you. Reintroduce yourself in a single short email before you add them to anything regular.
• Unsubscribes. Honor them immediately. Maildriply skips any recipient marked as unsubscribed when a campaign goes out, so a later send won't reach them by accident.

Step 6: Check whether recipients are reporting you

The strongest signal Gmail has is what its users do with your email. When someone clicks Report spam, that counts against you far more than any phrase in your subject line.

Google measures this as the user-reported spam rate, and its sender guidelines FAQ is specific: keep it below 0.1% and never let it reach 0.3%. Bulk senders above 0.3% lose eligibility for Google's mitigation until the rate stays below that line for seven days in a row. At 0.1%, one complaint per thousand emails is enough to be in trouble.

You can see your rate in Google Postmaster Tools after verifying your domain. Google notes that low-volume senders may not see any data there, so if you send a few dozen emails a day, you'll need to judge by replies instead. Watch for people asking to be removed, or replying with "who is this?". Both mean the email reached someone who didn't expect it.

The fix is almost never cleverer wording. It's sending fewer emails, to people with a clearer reason to want them. Our email tracking best practices explain how to use open and click data to decide who not to email again.

FAQ

Why are my emails going to spam when I send to just one person?

If it's one recipient, their own filters are the likely cause: a rule they set up, a corporate security gateway, or past messages from you that they marked as spam. Ask them to move your email out of spam and mark it "Not spam." If it happens across several unrelated recipients, work through the checklist above, starting with authentication.

Why are my Gmail emails going to spam all of a sudden?

A sudden change usually has a sudden cause. Look at what changed in the last week or two: a new campaign or a jump in volume, a new link or domain in your signature, a DNS change that broke SPF or DKIM, or a batch of contacts from a new source. Change that back first.

Does sending from @gmail.com instead of my own domain avoid spam?

It removes authentication setup from the list, because Google signs @gmail.com mail for you. It doesn't help with the other causes: bursts, risky links, bad lists, or complaints still count. For business email, a properly authenticated custom domain on Google Workspace usually looks more trustworthy to recipients.

Will asking recipients to mark my email "Not spam" fix it?

For those recipients, often yes: Gmail learns from what each user marks. It won't fix a problem that affects your whole domain, such as failing authentication or a high complaint rate. Use it for a few important contacts while you fix the underlying cause.

Maildriply sends through your own Gmail account with a single gmail.send permission, lets you check your domain's SPF, DKIM, and DMARC, and paces campaigns for you. See how it works, or connect your Gmail and send a test to your own inbox first.