26 November 2025

Why My Staging Site’s Emails Went to Spam but Production Was Fine and the Domain Alignment Fix That Solved It

Email deliverability can be a mysterious beast. One minute your messages are landing safely in inboxes, and the next they’re buried in the dreaded spam folder. Recently, we faced a puzzling issue: emails from our staging site were consistently going to spam, while those from the production environment sailed through just fine. Read on to learn what we discovered — and how a domain alignment fix saved the day.

TL;DR: Why This Happens and How We Fixed It

Even with identical codebases, staging and production environments can behave differently when it comes to email. In our case, the issue was an email authentication mismatch rooted in domain alignment problems. Email services like Gmail and Yahoo flagged our test messages as spam because the authenticated domain didn’t match the “From” address. Fixing our SPF and DKIM records and ensuring proper domain alignment solved the issue — and can help you avoid it too.

The Mystery: Identical Setups, Opposite Results

It started innocently: we pushed a new feature to our staging site and wanted to test the email notifications. The emails looked good on the surface, but no one on the team was receiving them. Or worse — they were landing in spam, or blocked entirely.

We double-checked everything:

• Same SMTP credentials on staging and production? Check.
• Email template logic identical? Check.
• Same “From” address in both environments? You bet.

And yet, only staging emails were getting flagged. So what was going on?

The Red Flag: Domain Misalignment

To get to the bottom of the mystery, we ran our email headers through tools like MXToolbox and Gmail’s “Show Original” view. That’s where we saw it — our staging site’s emails were failing SPF and DKIM checks due to a domain alignment error.

Here’s what we found:

• SPF (Sender Policy Framework): The IP that our staging mail was sent from wasn’t authorized in our records.
• DKIM (DomainKeys Identified Mail): The DKIM signature didn’t match the sending domain.
• DMARC (Domain-based Message Authentication, Reporting & Conformance): Because both SPF and DKIM failed or were misaligned, the whole message was flagged.

This trifecta is a red alert to email providers. If neither SPF nor DKIM aligns with the “From” domain, and DMARC is strict, your email is likely toast.

What is Domain Alignment, Really?

Domain alignment refers to whether the domain in your “From” address matches the domain authenticated by SPF and DKIM. If you’re sending from no-reply@myapp.com, but your SPF and DKIM are authenticated under mail.staging.myapp.com or even your-email-provider.com, that’s a mismatch — and a major red flag.

There are two types of alignment checks:

• SPF Alignment: Does the envelope “MAIL FROM” domain match the “From” address domain?
• DKIM Alignment: Does the DKIM “d=” domain match the “From” address domain?

DMARC will fail the entire message if neither of these are aligned and you’ve set up a strict policy. And service providers like Gmail scrutinize domain alignment especially closely.

Why It Happened Only in Staging

This part threw us off, because we expected consistency between environments. But here are a few reasons why domain alignment was fine in production and broken in staging:

1. Different subdomains: Our staging site used staging.myapp.com, whereas production used myapp.com.
2. SMTP routing via different servers: Even though we used the same email provider, the staging environment connected from an IP not included in our SPF record.
3. Different DKIM keys: Our production DKIM key was properly configured; staging didn’t have records for staging.myapp.com.

The Fix: Realigning the Stars (and Domains)

Once we diagnosed the root problem — misaligned domains — here’s what we did to fix it:

1. Add the Staging IP to the SPF Record

We updated our TXT SPF record in DNS like so:

v=spf1 ip4:192.168.1.10 include:emailprovider.com -all

We added the static IP our staging server used to send mail, ensuring SPF passed.

2. Set Up a DKIM Key for Staging

We generated a DKIM key pair and published the public key in our DNS records under default._domainkey.staging.myapp.com. This way, the signature matched the domain used in the “From” headers.

3. Adjust the DKIM Selector Settings

We made sure our mailer library or server used the correct selector and domain in the DKIM headers. Many email providers allow you to specify a custom domain or selector, even from the same account.

4. Revisit the From Address

As a bonus safety step, we changed our staging “From” address to explicitly use noreply@staging.myapp.com instead of myapp.com. This allowed us to align both SPF and DKIM cleanly with the subdomain.

5. Verify Everything with Online Tools

After updating DNS and redeploying the mail settings, we tested new staging emails using:

• Mail-Tester.com — for spam scores and authentication results
• MXToolbox — for SPF, DKIM, and DMARC validation
• Gmail’s “Show Original” feature — for header inspection

Everything checked out. Green lights across the board. For the first time, our staging emails landed confidently in our inboxes — not the spam folder abyss.

Better Practices for Staging Emails in the Future

This experience taught us a few hard lessons and good practices that we now follow religiously when setting up mail handling for any non-production environment:

• Use subdomains for staging emails (e.g., noreply@staging.myapp.com) and configure DNS accordingly.
• Whitelist staging IPs in SPF records if sending directly.
• Avoid using real production domains unless aligned properly.
• Monitor your DMARC reports to spot domain-alignment issues before they impact deliverability.
• Test frequently using authentication tools to catch silent failures.

Conclusion: A Healthy Fear (and Respect) for Email Authentication

Email is a complex protocol with lots of moving parts, but getting deliverability right is crucial — even in staging. Inconsistent behavior between environments can be frustrating, but they often reveal gaps in configuration. Domain alignment, especially under DMARC scrutiny, is becoming increasingly important. Understanding and fixing these issues not only restored our peace of mind — it leveled up our technical confidence too.

So next time you hit “Send” from staging and get radio silence, don’t just blame your email library. Follow the headers, align your domains, and you might just beat the spam filter before it ever sees you coming.