The Zeqo blog
Practical, jargon-free guides on email deliverability — for founders, agencies, and ecommerce teams whose revenue depends on reaching the inbox.
ERR_CERT_DATE_INVALID: The Fix When It's Your Site
If your own visitors are hitting NET::ERR_CERT_DATE_INVALID, the advice to check your system clock does not apply to you. Your certificate expired. Here is the fix, and the prevention.
Brevo Emails Going to Spam? The Deliverability Fix Order
Brevo campaigns in the spam folder usually trace back to an unauthenticated domain or a shared IP pool. Here is how to tell which, and what to fix first.
WooCommerce Emails Going to Spam? Stop Sending Through PHP Mail
WooCommerce order emails land in spam because WordPress sends them through the server's PHP mail function with no authentication. Here is what to replace it with.
Mailchimp Emails Going to Spam? Fix Authentication First
Mailchimp campaigns going to spam are usually an authentication or reputation problem, not a content one. Here is the order to check things in, and what to fix first.
SendGrid Emails Going to Spam? Start With Domain Authentication
Transactional mail through SendGrid hits spam for different reasons than marketing mail. Authentication, alignment, and shared IP reputation, in the order worth checking.
Microsoft 365 Email Authentication: SPF, DKIM & DMARC Setup Guide
Microsoft 365 doesn't sign with DKIM properly until you enable it per domain — and the CNAME setup trips almost everyone. Here's the full sequence.
Can You Have Two SPF Records? (No — and Here's How to Merge Them)
Adding a second SPF record doesn't add senders — it invalidates both. Here's the rule, and the correct way to merge.
Spamhaus Blacklist: How to Check, Understand, and Get Delisted
Spamhaus is the blocklist that actually matters. The delisting process is free and fast — if you fix the cause first.
Klaviyo Deliverability: Sending Domain Setup and Why Emails Go to Spam
Klaviyo's default shared sending domain means you inherit other senders' reputation. Here's the correct setup and the usual culprits behind spam placement.
Zeqo Mail vs MXToolbox: Which Should an Agency Actually Use?
MXToolbox answers “what does this record say right now?” Zeqo Mail answers “which of my 30 client domains broke this week?” They're different jobs.
Zeqo Mail vs dmarcian: DMARC Depth or Portfolio Coverage?
dmarcian goes deeper on DMARC than almost anyone. Zeqo Mail goes wider across domains and checks. Here's how to pick.
Zeqo Mail vs EasyDMARC: A Practical Comparison for Agencies
EasyDMARC gives you a full platform. Zeqo Mail gives you a scored portfolio and a fix to paste. Which one matches how you actually work?
The Best Free DMARC Tools in 2026 (Generators, Checkers, Analysers)
Free DMARC tools fall into three groups that solve three different problems. Here's which to use when, and where each free tier runs out.
What Is My DKIM Selector? How to Find It (Provider Lookup Table)
Your DKIM selector is the prefix in the DNS lookup — and most providers use a predictable default. Here's the table, and how to find yours if it isn't listed.
Pingdom vs UptimeRobot vs BetterStack (2026): An Agency's Honest Comparison
Three popular uptime tools, compared the way an agency actually buys: pricing, alerting, status pages, and what breaks when you're watching 30+ client sites.
Zeqo Watch vs Pingdom: Which Is Better for Agencies in 2026?
Pingdom is the enterprise veteran with RUM; Zeqo Watch is the agency-first newcomer. Here's the honest head-to-head.
Zeqo Watch vs UptimeRobot: The Agency-Focused Comparison (2026)
UptimeRobot is the cheap, no-frills favorite. Zeqo Watch trades the free tier for agency workflows. Here's how to choose.
Zeqo Watch vs BetterStack: Incident Management vs Agency Monitoring (2026)
BetterStack is built for dev teams who want on-call and incidents. Zeqo Watch is built for agencies watching client sites. Different jobs.
Shopify Emails Going to Spam? The Deliverability Checklist for Store Owners
A practical checklist for Shopify stores whose campaigns, abandoned cart flows, or order emails are landing in spam — with the DNS, reputation, and revenue fixes to check first.
Uptime Monitoring for Agencies: Watch 50 Client Sites From One Dashboard
Managing 30+ client sites in a spreadsheet is how agencies find out about downtime from the client. Here's the system that replaces it.
SSL Certificate Monitoring: Never Lose a Client to an Expired Cert
An expired certificate looks, to a client's customers, exactly like the site being hacked. Here's how to make sure it never happens on your watch.
DMARC Policy: When to Use p=none, quarantine, or reject
A DMARC record at p=none monitors but protects nothing. Here's when to move to quarantine or reject without breaking your own email.
Transactional Email Deliverability: Keep Password Resets and Receipts Out of Spam
Password resets, receipts, and product alerts cannot wait in spam. A practical deliverability checklist for transactional email.
Website Downtime Is Costing Your Agency Retainers (Here's How to Stop It)
The damage from downtime isn't the minutes offline. It's the client realizing they're watching the site more closely than you are.
SPF Record Syntax Explained: Includes, IPs, and the 10-Lookup Limit
SPF looks like one TXT record, but includes, redirects, and the 10-lookup limit can quietly break all your mail. Here's how to read it correctly.
Stop the “Is the Site Down?” Emails: Client-Facing Status Pages
A status page is the cheapest client-trust upgrade an agency can ship. Here's what to put on it and how to use it.
What Is a DKIM Selector? (And Why “DKIM Missing” Is Often Wrong)
Half the “your DKIM is missing” warnings are false alarms. The reason is the selector — what it is, where it lives, and how to check yours correctly.
How to Set Up SPF, DKIM & DMARC for Google Workspace (Step by Step)
New on Google Workspace? Here's the exact, copy-paste setup for SPF, DKIM, and DMARC — plus how to confirm all three actually pass.
Email Warm-Up: How to Build Sender Reputation Without Hitting Spam
Send 500 emails from a brand-new domain and you look exactly like a spammer. How to warm up the right way — and the ramp schedule to follow.
DMARC Reports Explained: How to Read Them and Fix What They Reveal
Set up DMARC and the reports start rolling in — as unreadable XML. What they actually tell you, and how to use them to lock down your domain.
SPF, DKIM & DMARC Explained: A Plain-English Guide for Founders
The three DNS records that decide whether your email lands in the inbox — explained without the jargon, plus how to check yours in 30 seconds.
Why Your Cold Emails Land in Spam (and How to Fix It)
Authentication is only half the battle. The real reasons outreach gets filtered — and a checklist to land in the inbox instead.
How to Check if Your Domain Is Blacklisted (and Get Delisted Fast)
A blacklisting can block your email overnight — without any warning. How to find out if you're listed, get removed fast, and avoid it happening again.
The Email Deliverability Checklist for Agencies Managing Many Client Domains
Twenty clients, twenty domains, twenty ways for email to silently break. A repeatable system for keeping every client's mail in the inbox.
Google & Yahoo Sender Requirements: The Checklist Every Sender Needs
Since 2024, Gmail and Yahoo enforce real rules for senders — miss them and your mail gets rejected. The complete checklist, explained simply.