Why Are My Emails Going to Spam? How to Fix Email Deliverability in 2026

Why Your Emails Are Going to Spam in 2026

If your business emails have started landing in spam — or worse, being silently rejected — you're not alone. Since 2024, Gmail, Yahoo, and Microsoft have enforced strict email authentication requirements. Emails that don't pass SPF, DKIM, and DMARC checks are increasingly sent to spam or blocked entirely.

This isn't a temporary glitch. It's a permanent shift in how email works. The good news: fixing it is straightforward once you understand what's going wrong.

The 2024–2025 Authentication Shift

In February 2024, Google announced new sender requirements for anyone sending email to Gmail addresses. Yahoo implemented similar rules simultaneously. Microsoft followed in May 2025 for Outlook.com, Hotmail, and Live.com.

The core requirement across all three providers: every email must be authenticated via SPF, DKIM, and DMARC. This applies to all senders — not just bulk mailers.

Before these changes, unauthenticated email would usually be delivered (perhaps with a warning). Now, it's increasingly sent to spam or rejected outright. If your business email configuration hasn't been updated to account for this shift, your deliverability has likely degraded.

The Three Authentication Checks

When your email arrives at Gmail, Outlook, or Yahoo, the receiving server performs three checks:

1. SPF (Sender Policy Framework)

Does your domain's DNS record authorise the server that sent this email? If the sending IP isn't listed in your SPF record, this check fails.

2. DKIM (DomainKeys Identified Mail)

Does the email carry a valid cryptographic signature that matches a public key in your DNS? If DKIM isn't configured for the sending service, this check fails.

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

Does the "From" domain align with the domain authenticated by SPF or DKIM? And what policy has the domain owner set for emails that fail? If you have no DMARC record, or if alignment fails, this check fails.

Failing any of these checks reduces your deliverability. Failing all three virtually guarantees your emails will land in spam.

Common Reasons Your Emails Are Going to Spam

No DMARC Record

Without a DMARC record, receiving servers have no policy to reference. Google and Yahoo now require at least a p=none DMARC record for bulk senders. Even for smaller senders, the absence of DMARC is a negative signal.

SPF Misconfiguration

Common SPF problems include:

• Missing services — your CRM, marketing platform, or helpdesk sends email as your domain but isn't in your SPF record
• Too many DNS lookups — exceeding the 10-lookup limit invalidates your entire SPF record
• Syntax errors — a malformed SPF record is treated as no record at all

Missing DKIM

Many email services require you to add DKIM DNS records manually during setup. If you skipped this step — or if a service was added to your domain without DKIM configuration — those emails lack DKIM signatures and fail this check.

DMARC at p=none

A p=none DMARC policy meets Google's minimum requirement for having a record, but it doesn't help your deliverability. It tells receiving servers "don't do anything special with failing emails" — which means it provides no positive reputation signal.

Progressing to p=quarantine or p=reject actually improves your deliverability, because it demonstrates you've verified all your legitimate sending sources and are confident enough to enforce authentication.

Domain Reputation

If your domain has been used to send spam (either by you inadvertently, or by spoofers exploiting your lack of DMARC enforcement), your domain reputation may be damaged. DMARC enforcement helps rebuild reputation by preventing unauthorised use of your domain.

How to Diagnose the Problem

1. Scan your domain with DMARC Busta's free scanner — it checks SPF, DKIM, and DMARC in seconds and tells you exactly what's misconfigured
2. Check email headers — when an email lands in spam, look at the message headers for Authentication-Results. This shows which checks passed and failed.
3. Review DMARC reports — if you have a DMARC record with reporting enabled, your aggregate reports show authentication pass/fail rates across all your sending sources

How to Fix Email Deliverability

Step 1: Publish a DMARC Record

If you don't have one, start with p=none to begin collecting reports. Use our free DMARC generator to create the correct record for your domain.

Step 2: Fix Your SPF Record

Ensure every service that sends email as your domain is listed in your SPF record. Check that you're under the 10 DNS lookup limit. Remove includes for services you no longer use.

Step 3: Configure DKIM

Each email-sending service needs DKIM configured. This typically involves adding DNS records provided by the service (e.g., Google Workspace, Microsoft 365, SendGrid, Mailchimp). Check each service's documentation for their specific DKIM setup instructions.

Step 4: Progress Your DMARC Policy

Once all legitimate sending sources are authenticated:

1. Move to p=quarantine — failing emails go to spam rather than the inbox
2. Monitor for 2–4 weeks — ensure no legitimate email is being quarantined
3. Move to p=reject — failing emails are blocked entirely

Reaching p=reject sends a strong positive signal to receiving servers. It demonstrates that you've verified all your legitimate email sources and are confident enough to block anything that fails authentication. This actively improves your deliverability.

Understanding Email Authentication Headers

When an email lands in spam, the message headers contain valuable diagnostic information. Here's how to read them:

Look for the Authentication-Results header in the email source. It shows the outcome of each check:

Authentication-Results: mx.google.com;
    spf=pass (sender IP is 209.85.220.41)
    dkim=pass header.d=yourdomain.com.au
    dmarc=pass (p=REJECT) header.from=yourdomain.com.au

In this example, all three checks pass — this email should be delivered normally. Compare this to a failing result:

Authentication-Results: mx.google.com;
    spf=fail (sender IP is 10.0.0.1)
    dkim=none
    dmarc=fail (p=NONE) header.from=yourdomain.com.au

Here, SPF fails (the sending server isn't authorised), DKIM is missing, and DMARC fails. With p=none, the email might still be delivered but is very likely to land in spam.

Common Email Services That Need Authentication

Most Australian businesses use several services that send email on their behalf. Each one needs to be authenticated. Here are the most common ones and what they require:

• Microsoft 365 — SPF: include:spf.protection.outlook.com. DKIM: enable in Microsoft 365 admin centre and add two CNAME records to DNS.
• Google Workspace — SPF: include:_spf.google.com. DKIM: generate key in Google Admin and add TXT record to DNS.
• Xero — SPF: include:mxvault.com. DKIM: available for custom domains in Xero settings.
• Mailchimp — SPF: include:servers.mcsv.net. DKIM: authenticate your domain in Mailchimp's settings.
• HubSpot — SPF: include:hubspot.com or via dedicated IP. DKIM: domain authentication in HubSpot settings.
• SendGrid — SPF: via sender authentication (adds include automatically). DKIM: CNAME records provided during domain authentication.

Missing even one of these services from your authentication configuration means those emails will fail SPF and potentially DKIM — degrading your deliverability for that service's emails.

How DMARC Busta Automates the Fix

Fixing email deliverability manually — especially across multiple email services and domains — is time-consuming and error-prone. DMARC Busta's Autopilot automates the entire process:

• Automatic DNS changes via Cloudflare, cPanel, or Route53 — no manual DNS editing
• AI source identification — automatically detects and authenticates your sending services from DMARC reports
• Safe DMARC progression — moves from p=none to p=reject at a safe pace, with automatic rollback if issues are detected
• SPF optimisation — manages your SPF record to stay under the 10 DNS lookup limit
• Ongoing monitoring — alerts you if authentication rates drop or new sending sources appear

The result: better deliverability, stronger domain reputation, and compliance with Google, Yahoo, and Microsoft requirements — all handled automatically.

Next Steps

1. Scan your domain to identify what's causing your deliverability issues
2. Review the report — it shows exactly what's configured, what's missing, and what needs fixing
3. Get started with DMARC Busta — free plan for monitoring, paid plans from $19/month for full Autopilot

Beyond Authentication: Other Deliverability Factors

While authentication is now the most critical factor for email deliverability, it's not the only one. Once your SPF, DKIM, and DMARC are properly configured, also check these common issues:

• Content quality — excessive use of ALL CAPS, too many exclamation marks, spam trigger words ("free money", "act now"), and image-heavy emails with little text can trigger spam filters.
• List hygiene — sending to invalid or inactive email addresses generates bounces, which damage your sender reputation. Regularly clean your mailing lists.
• Engagement metrics — Gmail and other providers track whether recipients open, click, or delete your emails. Low engagement rates signal that your emails aren't wanted, pushing future emails toward spam.
• Sending volume changes — a sudden spike in email volume (e.g., sending 10,000 emails when you normally send 100) triggers spam filters. Ramp up gradually when starting a new campaign.
• Blacklists — if your sending IP or domain is listed on email blacklists (Spamhaus, Barracuda, etc.), your emails will be blocked or filtered. Check your status at MXToolbox or similar services.

That said, in 2026, authentication failures are the number-one cause of deliverability problems for Australian businesses. Fix authentication first, then address these secondary factors.

For the full picture on compliance requirements driving these changes, see our guide on DMARC compliance in Australia for 2026. If you're concerned about email spoofing specifically, read how to stop email spoofing.