How To Fix Emails Going to Spam in Gmail

If your emails are landing in Gmail's spam folder, you're not alone — and it's rarely just one thing causing the problem. Gmail uses a layered filtering system that weighs authentication records, sender reputation, engagement history, and message content all at once. Fixing it means understanding which layer is failing you.

This guide walks through the most common causes and the concrete steps to address them, in order of impact.

Start With Authentication: SPF, DKIM, and DMARC

Gmail's filters treat unauthenticated mail with deep suspicion. Before anything else, verify that all three of these DNS records are correctly configured for your sending domain.

SPF (Sender Policy Framework)

An SPF record tells Gmail which servers are allowed to send email on behalf of your domain. If you're sending through an ESP or a third-party service and haven't added their sending infrastructure to your SPF record, Gmail may mark your messages as suspicious. Check your DNS for a TXT record starting with v=spf1. Make sure every service you send from is listed. Common mistakes include having more than one SPF record (you can only have one) or exceeding the 10 DNS lookup limit.

DKIM (DomainKeys Identified Mail)

DKIM adds a cryptographic signature to your outgoing messages. Gmail uses this to verify the message wasn't tampered with in transit and that it genuinely came from your domain. Most ESPs give you a CNAME or TXT record to add to your DNS. If DKIM isn't signing your mail, or if the selector is misconfigured, Gmail sees that as a red flag. Use a tool like MXToolbox to verify your DKIM record resolves correctly.

DMARC (Domain-based Message Authentication, Reporting and Conformance)

DMARC ties SPF and DKIM together and tells receiving servers what to do when one or both checks fail. A policy of p=none is a safe starting point — it lets you collect reports without affecting delivery. Once you've reviewed your DMARC reports and confirmed legitimate mail is passing, you can tighten the policy. Without any DMARC record at all, Gmail has no policy guidance from you as the domain owner, which weakens trust signals.

Check Your Sending IP Reputation

Gmail maintains reputation scores for sending IP addresses. If you're on a shared IP used by other senders who have poor practices, their behaviour affects you. If you recently moved to a new dedicated IP, you likely haven't built any reputation yet — which can also cause spam placement.

New dedicated IPs need a warm-up period: a gradual increase in sending volume over several weeks that lets Gmail observe consistent, engagement-positive sending before you ramp up to full volume. Skipping this step and sending large volumes from a cold IP is one of the most reliable ways to trigger spam folder placement.

You can check your IP's reputation using Google Postmaster Tools, which provides direct insight into how Gmail views your sending domain and IP. Look specifically at the Domain Reputation and IP Reputation dashboards. If either shows "Bad" or "Low," that explains your spam folder problem and tells you reputation repair is needed, not just technical fixes.

Improve Engagement Signals

Gmail pays close attention to how recipients interact with your emails. High spam complaints, low open rates, and large numbers of unengaged subscribers all drag your sender reputation down over time.

• Remove unengaged contacts. Subscribers who haven't opened anything in six or more months are hurting your reputation. Suppress or remove them.
• Make unsubscribing easy. A visible unsubscribe link reduces spam complaints. Gmail also looks for List-Unsubscribe headers — make sure your sending platform adds these.
• Segment and target. Sending relevant content to people who want it produces better engagement, which builds reputation. Blasting your whole list regardless of interest does the opposite.
• Monitor your complaint rate. Google Postmaster Tools shows your spam complaint rate directly. Gmail recommends keeping this below 0.10%, and anything approaching 0.30% puts your sending at serious risk.

Review Your Email Content

Content filters still matter, though they're less decisive than reputation signals. A few things that increase Gmail's spam score:

• Excessive use of promotional language ("FREE," "ACT NOW," "GUARANTEED") especially in the subject line
• A very high image-to-text ratio, or a single large image with no text
• Links that redirect through suspicious or unrelated domains
• Missing or broken plain-text version of your HTML email
• Sending from a free email address (Gmail, Yahoo, etc.) rather than your own domain

Sending from your own domain is non-negotiable for serious senders. It gives you control over your authentication records and your reputation — two things you cannot manage on a shared free address.

When Standard Fixes Aren't Enough

Sometimes the underlying problem is a burned IP, a domain with a history of complaints, or a sending situation that mainstream providers won't support. In those cases, working with a deliverability-focused service that can properly manage IP warm-up, authentication setup, and ongoing reputation monitoring makes a significant difference. Rainmail is built specifically for senders in that position — it handles the infrastructure side so you can focus on sending legitimate mail that reaches the inbox.

To get a clearer picture of where your current setup stands, run your domain through this free deliverability checker — it surfaces authentication gaps and reputation issues in one place.

The Short Version

Gmail spam placement almost always comes down to one or more of these factors: broken authentication, poor IP reputation, low engagement, or content issues. Fix authentication first — it's the foundation everything else builds on. Then address reputation and engagement. Content is the last layer to optimise, not the first place to look.

Deliverability isn't a one-time fix. It's an ongoing practice of monitoring your metrics, maintaining clean lists, and keeping your technical setup current as your sending evolves.