MailSlurp resources
Guides - Page 4
Practical guides for MailSlurp messaging, testing, reliability, extract, account setup, and procurement workflows.
Posts
SORBS Spam: What a Listing Means and How To Recover
Learn what a SORBS spam listing means, why senders show up there, and how to investigate IP, domain, auth, and complaint issues before they damage inbox placement.
Read moretechnicalSoft Bounce vs Hard Bounce: How To Tell the Difference and What To Do Next
Learn the difference between soft and hard bounces, which failures are temporary or permanent, and how to handle retries, suppression, and sender diagnostics without damaging deliverability.
Read moretechnicalSMTP Relay Services: How To Compare Providers for Application Send, Relay Control, and Release Safety
Compare SMTP relay services by workflow fit, sender controls, authentication, diagnostics, and testing needs so you choose the right provider for application email and relay operations.
Read moretechnicalSender Score Explained: How To Read It Without Misdiagnosing Deliverability
Learn what Sender Score measures, what a low score usually means, where it falls short, and how to use it with inbox placement and authentication checks.
Read moretechnicalReturn-Path in Email: What It Is and Why It Matters
Learn what the email Return-Path is, how it differs from From and Reply-To, and why it matters for bounces, SPF, and deliverability.
Read moretechnicalPermanent Error Evaluating DMARC Policy: Why It Happens and How To Fix It
Learn what the `permanent error evaluating DMARC policy` rejection means, which DMARC record mistakes trigger it, and how to repair the policy without breaking legitimate mail.
Read moretechnicalParts of an Email Address: Local Part, Domain, Aliases, and What Teams Should Actually Validate
Learn the parts of an email address, how the local part and domain work, and why aliases, normalization, and validation rules affect signup, routing, and deliverability.
Read moretechnicalOffice 365 DKIM Setup: Enable DKIM in Microsoft 365 Without Guessing the CNAMEs
Set up DKIM for Office 365 and Microsoft 365 custom domains without copying stale examples. Learn where Microsoft exposes the required CNAMEs, how selectors work, and how to verify live signing.
Read moretechnicalMessage Undeliverable: What It Means, Common Causes, and How to Fix the Real Failure
Learn what a message undeliverable error usually means, how to separate recipient, policy, size, and routing failures, and how to troubleshoot before blindly resending.
Read moretechnicalGoogle Workspace SMTP Relay: Setup, Ports, Auth, and Safe Testing
Set up Google Workspace SMTP relay without confusing it with smtp.gmail.com. Learn when to use smtp-relay.gmail.com, which ports and auth modes apply, and how to validate relay changes safely.
Read moretechnicalGoogle Workspace DMARC: Setup, Alignment, and Safe Rollout for Gmail Senders
Set up Google Workspace DMARC without treating it like a standalone TXT record. Learn how Gmail sender requirements, SPF, DKIM, alignment, and gradual enforcement fit together.
Read moretechnicalGoogle Workspace DKIM Setup: Generate the TXT Record, Turn It On, and Verify It
Set up Google Workspace DKIM without guessing. Learn how to generate the record in the Admin console, publish the TXT value, turn on signing, and verify real Gmail headers.
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