deliverlensRun Your First Deliverability Test ↗
Create a disposable inbox, send one message, and understand the first report without guessing what each state means.
2 min readDeliverlens help centre
Find the signal.
Fix the right thing.
Concise troubleshooting for authentication, DNS, reputation and inbox placement—grounded in the evidence you can actually verify.
Published guidance
Troubleshoot by question.
29 guides found.
2 guides
Getting Started
First-run setup, report basics, and where to begin.
Understand Your Deliverlens Score ↗
Learn how to read pass, warning, and fail signals so you can prioritize the changes that matter before you send at scale.
1 min read5 guides
Authentication
SPF, DKIM, DMARC, BIMI setup and alignment.
SPF Record Not Found? How to Fix Missing SPF (Step-by-Step) ↗
Understand why “SPF record not found” appears and fix it with a clean, valid TXT record that passes lookups and aligns with your From domain.
5 min readFix SPF, DKIM, and DMARC Failures Together ↗
Use a practical order of operations when authentication checks fail so you fix the sender identity first instead of chasing symptoms.
2 min readFix DKIM Selector Errors ↗
Resolve missing selectors, wrong public keys, and provider-side signing mismatches that cause `dkim=fail` or `dkim=none`.
1 min readSet Up a DMARC Policy That Is Safe to Roll Out ↗
Publish DMARC with the right alignment and reporting tags so you can move from monitoring to enforcement without breaking legitimate mail.
1 min readWhy BIMI Is Not Showing ↗
BIMI depends on stronger prerequisites than a single DNS record. Use this checklist when logos do not appear in inboxes.
1 min read3 guides
DNS & Infrastructure
Records, routing, MX, and delivery plumbing.
DNS Setup Checklist for Deliverability ↗
A compact checklist for the DNS and transport records that most affect mailbox trust and delivery consistency.
2 min readFix PTR and HELO Alignment Warnings ↗
Reverse DNS and HELO mismatches are classic trust issues for dedicated IPs and self-managed SMTP hosts.
1 min readMX Records and Routing Checks Explained ↗
Understand what MX warnings mean during provider migrations, domain onboarding, and routing cutovers.
1 min read2 guides
Account & API
API keys, account access, and basic customer setup.
Manage API Keys Safely ↗
Create, rotate, and revoke customer API keys without breaking existing automations or exposing the plaintext token twice.
2 min readAutomate Deliverlens With the API ↗
Use API keys, test creation, and polling to build pre-send checks into CI, staging, or release workflows.
1 min read2 guides
TLS & Transport Security
MTA-STS, TLS-RPT, DANE, and secure transport.
Set Up MTA-STS and TLS-RPT ↗
Add transport-policy and reporting records so you can enforce TLS expectations and observe failures in the wild.
1 min readUnderstand DANE and SMTP TLS Warnings ↗
Know when TLS warnings are informational, when they reflect real delivery risk, and when DANE is worth the operational cost.
1 min read3 guides
Reputation & Blacklists
IP/domain reputation, blocklists, warming.
Blacklist Removal Basics ↗
A blocklist alert is a symptom, not the whole problem. Use this sequence to confirm the listing, fix the cause, and request removal.
1 min readWarm Up New Sending Domains and IPs ↗
Reputation improves when volume, engagement, and authentication move together. Do not ramp blindly after a setup is technically valid.
1 min readDomain Age and New Sender Risks Explained ↗
Very new domains can trigger extra scrutiny even when DNS is technically correct. Use this guide when a sender domain is freshly registered or newly repurposed.
1 min read3 guides
Spam & Content Quality
Content, SpamAssassin, wording, formatting.
Improve Subject Lines and Content Quality ↗
Use this when the message itself is creating risk even after SPF, DKIM, and DMARC are already in good shape.
1 min readReduce Your SpamAssassin Score ↗
SpamAssassin is only one signal, but repeated warnings there often mirror the same issues mailbox providers dislike.
1 min readFix Attachment and Message Size Warnings ↗
Large messages, too many attachments, and image-heavy layouts make deliverability and user experience worse at the same time.
1 min read4 guides
Email Headers & Structure
Headers, MIME structure, message layout.
List-Unsubscribe and MIME Best Practices ↗
Many “small” email-structure warnings come from missing opt-out headers or weak multipart formatting.
1 min readUnderstand Message-ID and Received Headers ↗
Header warnings are easier to fix once you know which system creates them and which ones should remain stable across sends.
1 min readFix ARC Header and Validation Warnings ↗
ARC warnings matter most when mail passes through forwarders or mailing lists. Use this guide to decide whether the chain is optional, incomplete, or actively broken.
1 min readAdd One-Click Unsubscribe for Bulk Email ↗
Bulk mail increasingly needs one-click unsubscribe support, not just a footer link. Use this when Gmail or Yahoo flag missing one-click behavior.
1 min read2 guides
Links & External Resources
Link counts, redirects, safety, external assets.
Fix Link and Shortener Warnings ↗
Too many links or opaque redirect chains make your message look harder to trust, even when the content is legitimate.
1 min readAlign Landing Page Domains With the Sender ↗
Inbox trust improves when the domains inside your message feel consistent with the identity in the From address.
1 min read3 guides
Deliverability Monitoring & Tools
Ongoing monitoring, alerts, and diagnostics.
Build a Deliverability Baseline ↗
A single clean test is useful, but a stable pre-send baseline is what protects releases and provider changes over time.
1 min readWhen to Re-Run a Deliverability Test ↗
Not every template tweak needs a full recheck, but DNS, routing, and sender changes definitely do.
1 min readWhat to Do When Deliverlens Shows an Analyzer Error ↗
An analyzer error usually means the message could not be fully processed, not that your mail setup is automatically bad. Use this checklist before retrying or contacting support.
1 min read