Blog
Featured article
- 9 minutes read
Reverse DNS mismatch: Fix SMTP banner errors
Reverse DNS mismatch: Fix SMTP banner errors
Fix “reverse DNS does not match SMTP banner” errors by aligning PTR, A records, and server identity to restore trust and reliable email delivery.
Get our latest blogs delivered to your inbox each month
Scroll
All blog articles
- 21 minutes read
Adopt DMARC without an in-house DNS expert
Learn how to adopt and enforce DMARC without an in-house DNS expert. Understand common SPF, DKIM, and DMARC pitfalls, and see how managed services reduce risk.
- 17 minutes read
Email-first cybersecurity predictions for 2026
Explore key cybersecurity predictions for 2026, from AI-powered phishing to DMARC enforcement, BIMI adoption, SPF and DKIM limits, Zero Trust, and automation.
- 21 minutes read
No DMARC record found: Fix this critical mistake
Seeing a “no DMARC record found” error for your domain? Learn what it means, how it exposes you to spoofing and BEC, and how to move safely to p=reject.
- 15 minutes read
TLS 1.2: Why it still matters for secure email
TLS 1.2 remains vital for secure communication. Learn why it’s still widely used, how it compares to TLS 1.3, and how to strengthen your TLS posture.
- 21 minutes read
BEC: Explaining Business Email Compromise
Learn what Business Email Compromise (BEC) is, how to spot common scams, respond to attacks, and use SPF, DKIM, and DMARC to prevent future fraud.
- 10 minutes read
550 5.7.0 local policy violation: Reasons & fixes
Understand the 550 5.7.0 local policy violation error, common causes, and step-by-step fixes to restore email deliverability.
- 19 minutes read
PII in email: Explanation, risks, & protection
Understand what PII is, why email puts it at risk, and how your business can strengthen security to better protect sensitive information.
- 10 minutes read
DMARC bypass: Attack methods & advised solutions
Learn how attackers bypass DMARC by exploiting gaps in SPF, DKIM, and Microsoft, and the steps you can take to stop spoofed email from reaching inboxes.
- 13 minutes read
How to test email campaigns effectively
Learn how to test email campaigns before sending them. Improve deliverability, enhance engagement, and drive conversions.
- 20 minutes read
Spear phishing vs. phishing: Key differences
Learn the difference between spear phishing vs. phishing, how each attack targets your business, and the steps to protect customers, teams, and your domain.
- 20 minutes read
Email spammer bot: Risks and prevention
Learn what an email spammer bot is, how scraping works, and what DMARC does to protect your domain from abuse. Reduce risk and stop automated attacks.
- 9 minutes read
NCSC is retiring Mail Check & Web Check in 2026
The NCSC is retiring Mail Check and Web Check. Learn what the change means, when it takes effect, and why Sendmarc’s platform is the ideal replacement.
- 24 minutes read
Improve Gmail deliverability & avoid Spam folders
Gmail deliverability depends on authentication, reputation, and engagement. Learn how to avoid the Gmail Spam folder and ensure your emails reach the inbox.
- 9 minutes read
Queued email: What it means and how to fix it
Messages get queued for many reasons. Learn what a queued email is, how to fix it quickly, and how to prevent future delivery issues.
- 12 minutes read
Thinking of DMARC alternatives? What to do next
Explore DMARC alternatives and find out which controls reduce spoofing risk while you move safely toward full DMARC enforcement.
- 13 minutes read
BIMI lps tag: Multi-logo email branding explained
Learn how the BIMI lps tag enables multi-logo email branding by mapping local-parts to specific BIMI records. See how it works and common use cases.
- 12 minutes read
Recipient address rejected: access denied error
Learn why “recipient address rejected: access denied” errors occur, how to fix the issue, and the steps you can take to avoid it.
- 9 minutes read
Why anti-spam isn’t enough: Protect with DMARC
Anti-spam stops inbox threats. But only DMARC prevents domain impersonation. Discover why layered email protection is now essential for your business.