What DNS records are required to solve '450 4.1.8 Sender address rejected: Domain not found' errors?
Summary
What email marketers say13Marketer opinions
Email marketer from Sendinblue explains that email authentication helps verify your identity and improves deliverability rates. You should set up SPF (Sender Policy Framework) to specify which mail servers are allowed to send emails on behalf of your domain and DKIM (DomainKeys Identified Mail) to add a digital signature to your emails. These measures help prevent your emails from being marked as spam.
Email marketer from Neil Patel's Blog shares that to fix domain not found errors, focus on your DNS records. Ensure your MX records are correct so other mail servers know where to send emails for your domain. Also, set up SPF and DKIM records to authenticate your outgoing emails. These records help prove your emails are legitimate, reducing the chances of them being rejected.
Email marketer from Namecheap explains that MX records route incoming emails to the mail server. An A record maps a domain name to an IP address. SPF records allow you to specify the mail servers and domains that are authorized to send emails on behalf of your domain. DKIM records add a digital signature to outgoing emails. If the records aren't set up correctly, email may be rejected.
Email marketer from Stackoverflow explains that you need to check if you have an A record setup for your subdomain you're using for your SMTP connection in your control panel. Also, make sure your hostname matches the one you're using for SMTP.
Email marketer from Hostinger explains that issues with email delivery can often be traced back to DNS settings. Confirm that your MX records are accurately configured to point to the correct mail servers. Additionally, make sure your SPF record lists all authorized sending sources for your domain. These checks help ensure that receiving servers recognize and accept your emails as legitimate.
Email marketer from Mailjet Support explains that the 'Domain not found' error often results from DNS misconfigurations. You should ensure your MX records are correctly pointing to Mailjet's servers, and set up SPF and DKIM records to authorize Mailjet to send emails on your behalf. Incorrect DNS settings can lead to deliverability issues, so it's crucial to configure them properly.
Email marketer from Email Geeks indicates the error might be due to a lack of A/AAAA/MX records for the 5321 From Domain.
Email marketer from Email Geeks confirms that the 5321 From Domain has MX, SPF, and DKIM records but is missing A and AAAA records.
Email marketer from Reddit explains that to fix domain not found errors ensure your domain is resolving by checking it with a public DNS tool such as Google Admin Toolbox Dig or similar. Also, check your domain's MX, SPF, and DKIM records using the same tool.
Email marketer from DNSQueries explains that to diagnose a 'Domain not found' error, use an online DNS checker to verify the configuration of your MX records, A records, SPF records, and DKIM records. These tools will help you confirm whether the necessary DNS records are correctly set up and propagating properly, providing insights into potential misconfigurations.
Email marketer from Litmus explains that one of the reasons you may see an issue with emails not sending is because of the 450 4.1.8 error. Usually caused by the lack of proper DNS records that prove the sender is authorized to send on behalf of your organization.
Email marketer from cPanel suggests checking your SPF record. The SPF record is a DNS record that identifies which mail servers are authorized to send email on behalf of your domain. Make sure that your SPF record is properly configured and includes all of the mail servers that you use to send email.
Email marketer from EasyDMARC explains that an SPF record permits sending emails through authorized mail servers only. This record helps in email authentication and prevents spam. The domain owner lists authorized IP addresses and hostnames to send emails on behalf of the domain through the SPF record.
What the experts say3Expert opinions
Expert from Spam Resource highlights that ensuring proper DNS configuration is crucial for email deliverability. Specifically, the '450 4.1.8' error often points to issues with missing or misconfigured MX records. These records tell other mail servers where to deliver email for your domain. Additionally, setting up SPF and DKIM records is vital to authenticate your emails, which can help prevent them from being rejected.
Expert from Email Geeks explains the error message indicates a DNS error. The troubleshooting strategy involves performing DNS lookups (A and MX) for the domains in the 5321 and 5322 from addresses to verify the authoritative servers have the correct records.
Expert from Word to the Wise answers question about setting up SPF records, explaining that setting up Sender Policy Framework (SPF) properly lets email providers know that you have authorized them to send emails on behalf of your domain.
What the documentation says4Technical articles
Documentation from Digital Ocean explains that DNS records such as MX, A, SPF and DKIM records may not have propagated yet. DNS propagation can take up to 48 hours, though it usually completes much faster. Use online DNS lookup tools to check if your DNS records are visible globally.
Documentation from Microsoft Learn explains that the '450 4.1.8 Sender address rejected: Domain not found' error usually means the recipient's email server couldn't find your domain's DNS records. This often means the domain either doesn't exist or the DNS settings are incorrect. Specifically, make sure you have valid MX records pointing to your mail server, an A record for your hostname, and ensure your SPF and DKIM records are properly configured to authenticate your emails.
Documentation from RFC5321 details that SMTP requires forward-confirmed reverse DNS (FCrDNS). This means the sending server's IP address must have a PTR record (reverse DNS) that resolves to a hostname, and that hostname must have an A record (forward DNS) that resolves back to the original IP address. This validation helps prevent spam and confirms the legitimacy of the sending server.
Documentation from Google Workspace Admin Help details that to resolve the 'Domain not found' error, first verify that your domain is properly registered and active. Then, check your DNS settings. Ensure your MX records point to the correct Google mail servers (if using Google Workspace). Also, create SPF and DKIM records to authorize Google to send emails on behalf of your domain. This prevents your emails from being flagged as spam.