A practical guide to diagnosing and fixing email deliverability issues in 2025, with actionable steps for marketers and CRM teams.
What Is Email Deliverability and Why Does It Matter in 2025?
Email deliverability is the ability to land your emails in the recipient’s primary inbox—not spam, not promotions, not rejected. In 2025, with new filters and stricter policies from Gmail, Microsoft, Yahoo and Apple, it’s a mission-critical issue for any brand relying on email marketing.
Lost revenue
Damaaged domain reputation
Lower customer engagement
What’s Changed in 2025?
Gmail, Yahoo, AOL & Microsoft
The largest mailbox providers in the world are now far stricter, on what qualifies as a “good email”. What were best practices in the past, have now become must-have’s for all serious email senders.
Authenticate with SPF, DKIM, and DMARC
Keep consistently low spam complaint rates
Provide one-click unsubscribe links
Why Are Your Emails Going to Spam?
1. Your Domain Reputation Is Damaged
High bounce or complaint rates
You have new, cold IPs with a poor warming strategy
Sending to old emails or disengaged customers
2. Authentication Isn’t Correctly Set Up
Missing or misaligned SPF, DKIM, and DMARC records are red flags to inbox providers.
3. Content or Structure Triggers Spam Filters
Overuse of common marketing/spammy words in the content or misleading subject lines
Too many redirect links
The HTML to text ratio is imbalanced
Poorly constructed HTML
4. You’re Sending to Inactive Customers or Unverified Email Addresses
Continuing to communicate to addresses that haven’t engaged in months conveys that you don’t know your customers
How to Fix Deliverability Issues (Without Guesswork)
We recommend a professional audit to uncover issues across four key areas:
1. Authentication Review
We analyse your SPF, DKIM, and DMARC records to ensure they’re correctly configured
We help you with domain alignment.
2. Database Cleansing
We identify unengaged or bounced addresses
We can help you develop a data cleansing strategy
We help you build a sustainable segmentation and reactivation approach.
3. Sending Strategy Optimisation
We audit your current infrastructure, domain/IP setup, and cadence to design a deliverability-friendly approach.
4. Reputation Monitoring & Maintenance
We provide ongoing advice to maintain good sender reputation, so you stay out of trouble with leading mailbox providers
What Happens If You Don’t Act?
According to Validity’s 2023 Email Deliverability Benchmark Report, the average inbox placement rate is 83%, meaning nearly 1 in 5 emails may land in spam or go missing.
If even 10% of your marketing emails fail to reach the inbox, that’s a serious loss in potential revenue, conversions, and customer trust.
Frequently Asked Questions
How do I know if I have a deliverability problem?
Low enagement rates (such as clicks and opens), and inconsistent results across ISPs are common signs. If Gmail or Outlook users rarely engage, you may have inbox placement issues.
Is it just a technical problem?
No. While authentication is important, deliverability is also affected by data quality, user engagement, frequency, content and your domain/IP history.
How long does it take to recover from bad deliverability?
It depends on the root cause. Fixing authentication can be quick. Rebuilding reputation and trust with mailbox providers can take several weeks or longer.
Email Deliverability Is a Strategic Asset
In 2025, inbox placement is no longer a checkbox — it’s a competitive advantage. Brands that invest in a proper setup, strategy, and ongoing management will outperform those who don’t.
Get Expert Help with Your Deliverability
Martech Mavens provides tailored deliverability audits, consulting, and remediation services. We fix what’s broken and help you build a foundation that lasts.
