What is the fastest way to improve email deliverability?

Publishing a DMARC record and aligning your DKIM signature with your From domain are the two fastest high-impact fixes. Both can be done in under 15 minutes and immediately signal legitimacy to mailbox providers.

Why are my emails going to spam even with SPF and DKIM?

SPF and DKIM alone aren't enough — you also need DMARC alignment and proper domain configuration. Common causes include misaligned DKIM d= values, SPF records exceeding 10 DNS lookups, missing List-Unsubscribe headers, and sending to hard-bounced addresses.

How many DNS lookups are allowed in an SPF record?

SPF records are limited to 10 DNS lookups. Exceeding this limit causes SPF to return a permerror, which means authentication fails silently. Audit your SPF record regularly and flatten unnecessary includes.

Is one-click unsubscribe required for email senders in 2026?

Yes. Google and Yahoo require RFC 8058 one-click unsubscribe (via List-Unsubscribe-Post header) for bulk senders. Even senders below the bulk threshold benefit from adding it, as it reduces spam complaints and protects sender reputation.

How do I check if my sending IP is on a blocklist?

Use MXToolbox's blocklist checker to scan your IP across all major blocklists instantly. If listed, identify the root cause (usually a spam trap hit from stale list segments), fix the issue, then submit a delisting request through the blocklist's self-service process.

Email Deliverability Quick Wins: 7 Things You Can Fix Today

Your emails aren’t landing in the inbox.

You’ve got great content, a clean list, and a solid product — but 20% of legitimate email never reaches the inbox. That’s not a content problem. It’s an infrastructure problem.

Here are 7 quick wins you can implement today to move the needle on deliverability:

1. Publish a DMARC Record (Even at p=none)

If you don’t have DMARC, mailbox providers treat your domain as higher risk. A simple v=DMARC1; p=none; rua=mailto:[email protected] record tells ISPs you’re monitoring authentication — and gives you visibility into who’s sending as your domain.

Time to implement: 5 minutes.

2. Align Your DKIM Signature with Your From Domain

DKIM alignment means your d= value in the signature matches your visible From address domain. Misaligned DKIM is the #1 reason authenticated mail still fails DMARC. Check your ESP settings — most let you configure a custom signing domain.

Time to implement: 10–15 minutes.

3. Set Up a Dedicated Return-Path Domain

Your bounce address (Return-Path) should be on your domain, not your ESP’s default. SPF alignment depends on it. Create a subdomain like bounce.yourdomain.com, add the SPF record your provider gives you, and configure it in your sending platform.

Time to implement: 15 minutes.

4. Remove Hard Bounces Immediately

If you’re still sending to addresses that hard-bounced last week, ISPs are watching. Hard bounces tell mailbox providers you’re not maintaining your list — a strong spam signal. Configure your platform to suppress hard bounces on first occurrence, not after 3 attempts.

Time to implement: 5 minutes (one setting change).

5. Add a One-Click Unsubscribe Header

RFC 8058 one-click unsubscribe is now mandatory for bulk senders to Gmail and Yahoo. But even if you’re below the bulk threshold, adding the List-Unsubscribe-Post header reduces spam complaints by making it easy to leave — which protects your reputation far more than trapping subscribers.

Time to implement: 5–20 minutes (depending on ESP).

6. Check Your Sending IP Against Blocklists

Run your IP through MXToolbox right now. If you’re on even one blocklist, your inbox placement could be cratering silently. Most blocklists have a self-service delisting process — but you need to fix the root cause (usually a spam trap hit from a stale list segment) before requesting removal.

Time to implement: 2 minutes to check, 30 minutes to resolve.

7. Reduce Your DNS Lookup Count in SPF

SPF records are limited to 10 DNS lookups. Exceed that, and SPF returns permerror — meaning authentication fails silently. Audit your SPF record with a tool like dmarcian’s SPF survey. Flatten includes you no longer need and consolidate where possible.

Time to implement: 15–30 minutes.

The Bottom Line

None of these require a migration, a vendor switch, or a budget approval. They’re configuration-level fixes that compound over time.

The senders who consistently land in the inbox aren’t doing anything exotic. They’ve just closed the gaps that most teams overlook.

Which of these are you implementing first? Start with #1 if you haven’t already — DMARC visibility alone will change how you think about your sending infrastructure.

Email Delivery Pro helps organizations optimize their email infrastructure for maximum inbox placement. From authentication setup to ongoing reputation monitoring, we ensure your messages reach the people who need to see them.

Author

Harry Shuford

Harry Shuford is an IT specialist and technical writer with a focus on email delivery, deliverability, and the systems that power modern digital communication. With a strong understanding of the technical factors that influence email performance, he writes blog content that helps businesses better understand inbox placement, infrastructure, and best practices for reliable email delivery.