Why are emails being rejected with 'Domain of sender address does not exist' error?
Summary
What email marketers say9Marketer opinions
Email marketer from SMTP2GO suggests the absence of a PTR record for the sending IP address can result in an email being rejected. PTR records map IPs to domain names and are used to verify the server's identity, meaning that it is a best practice to set it up.
Email marketer from Stack Overflow responds that a "Domain of sender address does not exist" error indicates a DNS configuration problem. The sender's domain either doesn't have valid DNS records or the receiving server can't resolve them, suggesting a check of MX and A records.
Email marketer from Postmark suggests to implement proper email authentication (SPF, DKIM, DMARC) helps to verify the email's authenticity. When these are set up, receiving servers are more likely to trust your emails.
Email marketer from MXToolbox shares that "Domain of sender address does not exist" usually means the receiving server can't find the sender's domain in DNS. They advise using MXToolbox to check the sender domain's DNS records, especially MX and A records, for errors or missing information.
Email marketer from Reddit explains that a common cause is a typo in the sender's email address, particularly the domain part. They suggest double-checking the spelling and ensuring the domain is correctly entered.
Email marketer from EmailDeliveryTips explains that if the domain used in the "From" address is invalid or not properly configured, the recipient mail server will reject the email. A valid, existing, and properly configured domain name is essential for sending emails.
Email marketer from Spiceworks highlights an invalid domain used in the sender's email address. Sometimes, senders use domain names that do not resolve to any IP address, thus causing emails to be rejected. Ensure to only use valid domain names.
Email marketer from EasyDMARC suggests to configure your SPF record correctly. An incorrect SPF record can cause the recipient server to think the email is not sent from an authorized source, leading to rejection. Check and update your SPF record with all sending sources.
Email marketer from Google Groups indicates that a likely cause is the sender's domain is new and hasn't fully propagated across the internet's DNS servers. Propagation can take up to 48 hours. They advise waiting and trying again.
What the experts say5Expert opinions
Expert from Email Geeks shares an experience with Salesforce clients encountering "does not exist" rejections when sending to themselves. This was due to tightly controlled internal DNS not recognizing the zone delegation for the domain/subdomain pointed at Salesforce Marketing Cloud. The solution involved duplicating DNS entries internally or allowing the server to follow the delegation.
Expert from Email Geeks explains that the rejection message `smtp;553 5.1.8 Domain of sender address does not exist` often indicates the envelope from does not resolve in DNS. They suggest checking the logs on the inbound MX servers for more details about hostname checks and errors. Steve also suggests that the company might have special-cased DNS for their own domains, causing DNS lookup issues internally.
Expert from Word to the Wise responds by suggesting that the domain used in the 'From' address must resolve properly. This error can occur if the domain is newly registered and DNS propagation hasn't completed, or if there's an issue with the domain's DNS records. Suggests double-checking the MX records and A records of the sending domain.
Expert from Spam Resource explains that the "Domain of sender address does not exist" error often stems from stringent spam filtering measures. Receiving servers are increasingly verifying the legitimacy of sender domains. Ensure the domain is properly registered, has valid DNS records, and is not listed on any blocklists.
Expert from Email Geeks states that the issue is not with the ESP but with something broken on the MX cluster. Provides definitive check with nc command.
What the documentation says3Technical articles
Documentation from Microsoft Learn explains that the '550 5.1.8' error (Domain of sender address does not exist) indicates that the sender's email address domain is not found in DNS. This can occur due to typos in the email address, DNS configuration issues on the sender's side, or the domain genuinely not existing.
Documentation from cPanel Documentation explains that the "Domain of sender address does not exist" error (550 or similar) means the recipient server cannot resolve the sender's domain. This could be due to DNS issues, a newly registered domain that hasn't propagated, or the sender using a non-existent domain. Check DNS records and domain registration.
Documentation from Exim Wiki explains that sender verification (verp) failures often result in "Domain of sender address does not exist" errors. This occurs when the receiving server tries to verify the sender's address and fails to resolve the domain. Configuration errors on the sender's or receiver's side can cause this.