Category
Landing in the inbox: spam filters, sender reputation, SPF, DKIM, DMARC, and domain warm-up.
10841 posts
Fix the 'invalid version string' error in your email's Mime-Version header. Learn the root causes, how to validate and correct it, and how to test.
Stop malicious SVGs in emails with data URIs from executing scripts. Learn how to detect and block this vulnerability to protect your inbox placement and.
Ensure your DKIM records are properly formatted with real-time verification. Prevent delivery issues and improve sender reputation with accurate DNS.
Fix multiple v=spf1 declarations in your SPF record with this step-by-step guide. Prevent email delivery failures and maintain sender reputation with.
Stop inflating your spam score. Learn how hidden form elements with action=malicious trigger spam filters and how to verify your list to prevent.
Protect your email deliverability by ensuring SPF records don’t expire. Use real-time verification and inbox testing to catch issues before they impact.
Ensure your outbound emails pass DKIM checks across multiple domains. Learn how to maintain consistent signing, avoid delivery failures, and improve.
Ensure your emails pass DMARC checks by testing how recipient servers enforce p=quarantine. Use MailTester’s real-time verification to catch failures.
Ensure your SPF record allows IPv6 sending IPs by verifying against real delivery data. Avoid bounces and protect sender reputation with accurate SPF.
Fix SPF include domain issues causing verification failure. Learn how non-compliance breaks email authentication and how MailTester's real-time API.
Resolve SPF softfails caused by non-RFC-compliant reply-to domains. Learn how to verify and clean your list to improve deliverability and sender.
Fix SPF exp field errors 550 caused by missing or excessively long explanations. Learn how to correct DNS records for proper email deliverability.
