The Inbox Decay blog
Email deliverability in plain English — what actually breaks, why, and the exact fix. No folklore.
18 July 2026 · Jason
Why are my emails suddenly going to spam? The six causes, in order
Sudden spam-foldering means something changed. The six changes that actually cause it, ordered by how often they're guilty, and how to identify yours in minutes.
17 July 2026 · Jason
Constant Contact emails going to spam? The setting nobody turned on
Constant Contact works out of the box, which is exactly the problem: self-authentication is optional-looking and off by default. What it does, how to enable it, what to check.
16 July 2026 · Jason
beehiiv newsletter going to spam? Look at the orange cloud first
The most common beehiiv delivery failure is a Cloudflare setting, not a missing record. The proxy trap, the DMARC rule beehiiv enforces, and how to verify both in a minute.
15 July 2026 · Jason
MailerLite emails going to spam? The two-SPF mistake that breaks everything
MailerLite setup is two records, and one wrong move while adding them silently breaks email authentication for every tool you send with. How to check, and the merge that fixes it.
14 July 2026 · Jason
Brevo emails going to spam? 'Verified' doesn't mean authenticated
Brevo's green checkmark proves you own the domain, not that your emails are signed by it. The DKIM records that actually matter, and how to tell which generation yours are.
13 July 2026 · Jason
Klaviyo emails going to spam? You're probably checking the wrong domain
Klaviyo setups live on a subdomain like send.yourstore.com, and that detail breaks more diagnoses than any missing record. Where to actually look, and what to fix.
12 July 2026 · Jason
Kit emails going to spam? The 10-minute fix (and the trap that makes it worse)
Most Kit spam problems trace back to two missing DNS records. The exact fix, in plain English, plus the DMARC mistake that quietly makes everything worse.
12 July 2026 · Jason
Mailchimp emails going to spam? Check these two CNAME records first
Most Mailchimp spam problems come down to k1._domainkey, a DNS dashboard that mangles it, or a DMARC record nobody added. The fixes, in plain English.