Why Your Emails Aren’t Reaching the Inbox in 2025 – And What to Do About It

A practical guide to diagnosing and fixing email deliverability issues in 2025, with actionable steps for marketers and CRM teams.

Email deliverability is the ability to land your emails in the recipient’s primary inbox—not spam, or 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.

In the last 18 months, email deliverability standards have shifted dramatically. The largest mailbox providers in the world are now far stricter about what qualifies as a “good email.” What were once considered best practices have become non-negotiable requirements for serious senders. Inbox providers are placing more emphasis than ever on security, engagement, and trust. In early 2024, Gmail and AOL/Yahoo jointly introduced stricter sender requirements, marking a coordinated shift in industry standards. Microsoft has since raised the bar even further with additional measures.  Since May 2025, Microsoft has implemented even stricter filtering measures, with a growing number of issues reported by senders targeting Microsoft domains such as hotmail.com,  live.com, and outlook.com.

Since February 2024, Google requires bulk senders (5,000+ daily) to:

AOL and Yahoo were not just followers,  they jointly announced updated requirements alongside Google in October 2023. These rules took effect in Q1 2024 and are virtually identical to Gmail’s, as outlined above.  This move marked a rare but significant collaboration between mailbox providers to standardise sender expectations; making proper authentication and complaint control non-negotiable across most consumer inboxes.

Apple continues to mask open data and limit tracking making engagement signals less reliable.  This forces senders to have better database management and consider better engagement KPIs.

From the 5th May 2025, Microsoft officially introduced new sender requirements, bringing its enforcement in line with Gmail and Yahoo, and going further in some key areas. The most notable change is Microsoft’s strict enforcement of alignment: authenticated mail must not only pass SPF, DKIM, and DMARC, but these mechanisms must be aligned.

Key points of Microsoft’s 2025 update include:

There’s often no single reason why an email lands in the spam folder; usually it’s the result of several small issues adding up. From misconfigured authentication to low engagement or reputation scores, mailbox providers use complex algorithms that assess multiple signals before deciding whether to deliver, junk, or block a message. While this section highlights the some common and fixable causes, it’s not an exhaustive list — which is why a detailed deliverability audit is often essential.

We recommend a professional audit to uncover issues across four key areas:

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.

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.

No. While authentication is important, deliverability is also affected by data quality, user engagement, frequency, content and your domain/IP history.

It depends on the root cause. Fixing authentication can be quick. Rebuilding reputation and trust with mailbox providers can take several weeks or longer.

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.