Your DKIM keys are probably too short—and Gmail knows it
The sound of rain on warehouse windows in Portland; the smell of wet cardboard outside a fulfilment centre in Milton Keynes; the flicker of a monitor in a spare bedroom in Austin where someone’s just realised their newsletter stopped reaching Gmail inboxes three days ago.
DKIM keys shorter than 2048 bits now fail at Gmail and Yahoo
If you set up email authentication before 2022, your DKIM keys are likely 1024-bit—and silently killing deliverability.
If you set up DKIM before 2022 and have not touched it since, you may be running 1024-bit keys. In 2026, 2048-bit is the minimum acceptable standard. In January 2025, a SaaS startup watched their cold outreach pipeline collapse in 72 hours. Open rates dropped from 38% to under 2%. The culprit was not bad copy or a weak offer. It was three lines of broken DNS configuration.
The problem is not theoretical. Google and Yahoo’s bulk sender requirements, which took full effect in 2024, changed the rules permanently. Send more than 5,000 emails per day to Gmail addresses and you must have SPF or DKIM authentication, a DMARC policy, and one-click unsubscribe. But the enforcement around key strength is new. As per Google and Yahoo’s sender requirements, your spam rates must be 0.3% or lower. But ideally, your spam complaint rate target should be below 0.1%. Weak keys push you over that threshold fast.
Check your key size using Mail-Tester.com (free for two tests per day) or GlockApps ($79/month for the Pro plan). Also: rotate your DKIM keys at least annually. If your private key is ever compromised, an attacker can forge authenticated mail from your domain indefinitely until you rotate. Most ESPs—Mailchimp, ConvertKit, Beehiiv, Kit—will regenerate keys through their domain settings panel. If you’re on a dedicated IP or self-hosted SMTP, you’ll need to regenerate via your mail server config and update DNS. The fix takes fifteen minutes. The cost of ignoring it is three months of inbox placement slowly decaying until you notice.
WATCH OUT
WordPress transactional mail is probably routing through the wrong SMTP server
Most operators don’t realise WP Mail SMTP and similar plugins can send password resets, form notifications, and order confirmations through the same marketing ESP you use for newsletters. When a transactional message hits a spam trap or gets flagged, your entire domain reputation takes the hit—not just your broadcast list. The fix is to split transactional and marketing sends across separate subdomains or separate providers entirely. Mailgun, Postmark, and Amazon SES all offer transactional-only plans starting at $10/month or pay-per-message. If you’re on Mailchimp or Kit for broadcasts, route transactional mail somewhere else.
ANALYTICS
Custom events in GA4 fail silently—here’s where to look first
You’ve instrumented custom events in Google Analytics 4, but nothing appears in reports. No error messages, no warnings, no feedback loop. GA4’s event pipeline drops malformed payloads without telling you why. The most common failure points: parameter names longer than forty characters, reserved event names like ‘session_start’, and events fired before the gtag config loads. Open the DebugView panel in GA4, enable debug mode in your GTM container or add ‘?debug_mode=true’ to your URL, and watch the real-time event stream. If nothing appears, your events aren’t reaching Google at all. If they appear but don’t populate standard reports, your parameter schema doesn’t match GA4’s expectations.
SPONSORSHIP
Rate cards inflate list size—show open cohorts instead
Most sponsorship rate cards lead with total subscriber count. That number is meaningless to a sponsor evaluating CPM. What matters is how many people opened your last four emails, clicked a link in the past thirty days, or engaged with a previous sponsor CTA. Pull a ninety-day engagement cohort from your ESP, break it into opened / clicked / converted, and put those numbers in your deck. ConvertKit’s subscriber scoring export and Beehiiv’s engagement data both give you the raw counts. If 60% of your 10,000-subscriber list hasn’t opened an email in six months, your effective reach is 4,000—and sponsors will figure that out after the first campaign underdelivers. Leading with engagement data closes deals faster because it eliminates the negotiation over what your list is actually worth.
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