Emails going to spam? Here's what to check first
Use this quick checklist to identify the most common reasons emails land in spam. Work through each check in order — most deliverability problems are found and fixed within the first three steps.
Missing SPF, DKIM, or DMARC
Without SPF, DKIM, and DMARC, receiving servers cannot properly verify your domain identity. Missing authentication increases spam scores and makes spoofing easier.
SPF verifies sending servers, DKIM signs messages cryptographically, and DMARC tells receivers how to handle authentication failures.
Many spam folder problems are caused by domains using only SPF or using DMARC with p=none and no enforcement.
Your domain or server is blacklisted
Mail servers and sending IPs can appear on DNS blacklists because of spam complaints, compromised accounts, malware, or poor list hygiene.
Major providers check DNSBL services such as Spamhaus, Spamcop, and Barracuda as part of their filtering pipeline.
If your sending IP is blacklisted, emails may go directly to spam or be rejected entirely.
Poor sending reputation
Email reputation is based on user behaviour and historical sending quality.
High bounce rates, spam complaints, sudden volume spikes, and sending to invalid addresses all damage reputation.
Even with correct SPF, DKIM, and DMARC, poor reputation can still cause spam placement.
SMTP TLS or transport security problems
Modern mail providers expect encrypted mail transport using STARTTLS.
Expired certificates, invalid TLS chains, or missing STARTTLS support can reduce trust and negatively affect deliverability.
MTA-STS and TLS-RPT improve transport security and visibility into TLS failures.
Content and formatting issues
Spam filters also analyse message content.
Misleading subject lines, excessive links, attachment abuse, spam-like wording, invisible text, and malformed HTML emails can trigger filtering systems.
Deliverability problems are often a combination of authentication and content quality.
How to diagnose deliverability problems
Start by checking SPF, DKIM, DMARC, MX, blacklist status, SMTP TLS, MTA-STS, BIMI, and TLS-RPT.
The fastest way to audit everything is to run a complete MXFend Email Security Score scan.
Frequently asked questions
Can emails go to spam even if SPF passes?
Yes. SPF is only one signal. Reputation, DKIM, DMARC alignment, blacklist status, content quality, and user engagement also affect inbox placement.
Does DMARC stop emails from going to spam?
DMARC helps protect domain identity and spoofing, but it does not guarantee inbox placement. Reputation and content quality still matter.
Can blacklists cause Gmail spam placement?
Yes. DNS blacklist listings can affect reputation and increase the chance of spam filtering or outright rejection.
What is the fastest way to troubleshoot deliverability?
Run a complete MXFend Email Security Score scan to check authentication, blacklist status, SMTP TLS, and transport security issues in one report.