Why Are My Emails Going to Spam? A Troubleshooting Guide

Modern spam filters use hundreds of signals to determine whether an email belongs in the inbox or spam folder. Understanding these signals is the first step to fixing deliverability.

The major factors are:

• Sender reputation: Your IP and domain reputation scores (checked against blacklists and reputation databases).
• Authentication: Whether SPF, DKIM, and DMARC pass and align.
• Content analysis: The words, formatting, and structure of your email.
• Engagement history: How recipients have interacted with your previous emails (opens, clicks, replies, spam reports).
• Sending patterns: Sudden volume spikes, inconsistent sending patterns, or sending to many invalid addresses.

Email providers like Gmail, Outlook, and Yahoo each have their own spam filtering algorithms, so an email might reach the inbox at Gmail but land in spam at Outlook.

Missing or broken SPF record: If your domain doesn't have an SPF record, or if the sending server isn't listed in it, many providers will flag the email. Use LookMyIP's DNS Lookup to check your SPF record.

Missing DKIM signature: Emails without DKIM signatures are treated with more suspicion. Most email providers and marketing platforms support DKIM — make sure it's configured.

No DMARC record: Without DMARC, there's no policy telling receivers how to handle authentication failures. Even a p=none DMARC record is better than no DMARC at all.

SPF/DKIM alignment failure: DMARC requires that the domain in the "From" header matches either the SPF-authenticated domain or the DKIM-signing domain. Misalignment is a common cause of deliverability issues, especially when using third-party sending services.

Fix: Check all three records using LookMyIP's DNS Lookup tool. Send a test email to Gmail and inspect the "Show original" headers to see SPF, DKIM, and DMARC pass/fail status.

Blacklisted IP: If your sending IP is on a DNSBL (DNS-based Blackhole List), many receiving servers will reject or junk your email. Check using LookMyIP's Blacklist Checker.

Low domain reputation: Even if your IP is clean, email providers track domain reputation separately. A new domain with no sending history has a neutral reputation that needs to be built up gradually.

Shared IP issues: If you use a shared sending IP (common with email marketing platforms on their lower tiers), other senders on that IP can damage its reputation, affecting your deliverability.

Previous owner's reputation: If you purchased an expired domain or were assigned a previously-used IP, you may inherit negative reputation. Check your IP's reputation using LookMyIP's IP Reputation Checker.

Fix: Monitor your reputation with Google Postmaster Tools and Microsoft SNDS. If blacklisted, fix the root cause and request delisting. For critical email, consider a dedicated sending IP.

Spam trigger words: Words like "FREE!!!", "Act now!", "Click here!", and excessive exclamation marks raise spam scores. Write naturally and avoid aggressive sales language.

Image-heavy emails: Emails that are mostly images with little text look suspicious to spam filters. Maintain a healthy text-to-image ratio.

Broken HTML: Malformed HTML, inline CSS issues, and non-responsive designs can trigger spam filters. Use a reputable email template builder and test across clients.

Misleading subject lines: Subject lines that don't match the email content, use RE:/FW: prefixes deceptively, or contain ALL CAPS increase spam risk.

Missing unsubscribe link: Marketing emails without a one-click unsubscribe mechanism are increasingly penalized. Gmail and Yahoo require this for bulk senders.

URL shorteners: Using bit.ly or similar URL shorteners in emails is a major red flag because spammers frequently use them to disguise malicious URLs.

No warmup: Sending a large volume of email from a new IP or domain without gradually ramping up is the fastest way to land in spam. Warm up by sending to small, engaged audiences first and increasing volume over 2–4 weeks.

High bounce rate: Sending to many invalid email addresses signals poor list hygiene. Keep hard bounce rates below 2%. Remove bounced addresses immediately.

High spam complaint rate: If more than 0.1% of recipients mark your email as spam, your reputation drops quickly. Gmail's Postmaster Tools shows your spam complaint rate.

Purchased email lists: Never send to purchased or scraped email lists. The recipients didn't consent, bounce rates will be high, and spam complaints will destroy your reputation.

Inconsistent sending: Sending nothing for months and then blasting a large campaign looks suspicious. Maintain a consistent sending schedule.

Fix: Use double opt-in for list building, clean your list regularly, monitor bounce and complaint rates, warm up new IPs/domains gradually, and always provide easy unsubscribe options.