Why is my IP address not authorized to send email and how do I fix it?
Summary
What email marketers say12Marketer opinions
Email marketer from Email on Acid explains the importance of maintaining a clean IP reputation. Email On Acid shares that a poor IP reputation can lead to deliverability issues, including authorization errors. It suggests best practices such as warming up your IP address gradually, segmenting your email list, and monitoring bounce rates.
Email marketer from Email Geeks shares the bounce message they received: "550-5.7.1 [x.x.x.x] The IP you're using to send mail is not authorized 550-5.7.1 to send email directly to our servers. Please use the SMTP relay at 550-5.7.1 your service provider instead."
Email marketer from GlockApps shares information on IP warming which is the process of gradually increasing the volume of emails you send from a new IP address, is crucial to build a positive reputation with mailbox providers and avoiding deliverability issues.
Email marketer from Email Geeks quotes Google's help article: “The determination of whether or not an IP address is authorized to send mail is made by the ISP that provides you with the IP address.” and asks if the user checked with the ISP.
Email marketer from Zerobounce shares what a spam trap is and that they are email addresses that are used to identify and block spammers which cause your emails to not be received.
Email marketer from Email Marketing Forum states that if you're on a blocklist, identify which one and follow their specific delisting process. They note that each blocklist has its own requirements, and you'll need to demonstrate that you've addressed the issues that led to the listing. They also advise against using third-party delisting services, as they are often ineffective.
Email marketer from Reddit suggests using an SMTP relay service (like SendGrid or Mailgun) if you're encountering authorization issues. This avoids sending directly from your IP and relies on a reputable sender's infrastructure. They explain that relay services handle the necessary authentication and reputation management.
Email marketer from EmailFAQ shares that a common reason for this error is that your IP address has been blacklisted due to spam activity. It could also be due to misconfigured DNS records (SPF, DKIM, DMARC). They suggest checking blacklists and ensuring proper authentication.
Email marketer from Mailjet shares that checking your IP reputation is vital for determining the deliverability of your emails and also shares various sites that can be used to check your IP reputation.
Email marketer from MailerQ shares that there are various blocklists with different requirements for being put on the list. Some blocklists are based on spam traps, some are based on honeypots.
Email marketer from Email Geeks responds to a question about delisting from PBL by suggesting to only talk to your ISP.
Email marketer from StackOverflow suggests that this issue is often related to reverse DNS (PTR) records. The user suggests that if the IP address doesn't have a matching PTR record pointing back to your domain, mail servers may reject the connection as unauthorized. They advise configuring the PTR record with your ISP.
What the experts say6Expert opinions
Expert from Spamresource explains that a common reason for IP address authorization issues is a poor IP reputation. They shares that this often stems from sending unsolicited emails (spam), and that the best way to fix this is to clean up your sending practices, authenticate your email, and request delisting from blacklists.
Expert from Email Geeks explains that the PBL is the “policy block list” and is a list of IPs that are prohibited by the policy of the ISP that owns them from sending mail directly. The ISP is saying that they’re not allowed to send mail from that IP space and Google and the PBL are listening.
Expert from Email Geeks states that the user's ISP is the relevant party and the user needs to talk to them.
Expert from Word to the Wise shares a check list for senders to keep and maintain their sending reputation in a good state.
Expert from Email Geeks responds to a question about delisting from PBL by stating the user needs to talk to their ISP.
Expert from Word to the Wise explains PTR records and notes that they help to ensure the IP address has an associated hostname which is critical for deliverability.
What the documentation says5Technical articles
Documentation from MXToolbox explains that they provide tools to diagnose email server issues. It notes that one cause of this error is if you are on a blacklist, to check the blacklist status of your IP address with their tool to confirm. They suggest contacting the blacklist maintainer for delisting if applicable, and also validating your DNS records.
Documentation from RFC shares information about SPF records. They explain that SPF records authorize the IP addresses that are allowed to send email on behalf of your domain. If your sending IP isn't included in the SPF record, receiving servers may reject the email as unauthorized.
Documentation from Microsoft Learn explains that a "550 5.7.1" error often indicates a sender authentication failure. This can be due to issues with SPF, DKIM, or DMARC records. They recommend verifying that your domain's DNS records are correctly configured to authorize your sending IP address.
Documentation from DMARC.org shares what DMARC is (Domain-based Message Authentication, Reporting & Conformance) to explain that DMARC builds upon the SPF and DKIM protocols and helps prevent email spoofing and phishing attacks.
Documentation from Google Workspace Admin Help explains that the error "550 5.7.1 ... The IP you're using to send mail is not authorized" means the IP address you're using to send email isn't authorized to send directly to their servers and recommends using your ISP's SMTP relay. They link to further troubleshooting steps.