Summary
The error message "The IP you're using to send mail is not authorized to send email directly to our servers" indicates a critical issue preventing your emails from reaching recipients. This typically means the receiving mail server has flagged your IP address as unauthorized. The primary cause often stems from your IP being listed on a blocklist (or blacklist), particularly a Policy Block List (PBL) like Spamhaus PBL, which prohibits direct sending from certain IP ranges based on ISP policies. This can also be due to misconfigurations in email authentication protocols such as SPF, DKIM, or DMARC, which verify your domain's sending legitimacy.
Key findings
- IP blocklist impact: Google and other major email providers often reject emails from IP addresses found on public blocklists like Spamhaus, as this helps prevent spam and unauthorized sending.
- Policy block lists (PBLs): These lists are maintained by ISPs and are designed to prevent direct email sending from IP ranges that should only be used for end-user connections, not for server-to-server mail transmission. If your IP is on a PBL, it means your ISP's policy prohibits direct mail sending from it.
- ISP responsibility: The authorization status of an IP address to send mail is determined by the internet service provider (ISP) that owns and provides that IP. Any delisting or policy changes must typically be handled by the ISP.
- SMTP relay requirement: The error explicitly advises using an SMTP relay provided by your service provider, indicating that direct sending from your current IP is not permitted.
- Authentication issues: Problems with SPF, DKIM, and DMARC records can also lead to rejection, as these protocols ensure your sending IP is authorized by your domain's DNS records. For more details on these, see a simple guide to DMARC, SPF, and DKIM.
Key considerations
- Contact your ISP: If your IP is on a PBL, only your ISP can remove it or confirm their policy regarding direct mail sending. This is the most crucial first step.
- Check blocklists: Verify if your IP address is listed on major blocklists, especially Spamhaus PBL. You can check your IP at Spamhaus Lookup. If you find your IP on any blocklist, learn more about how to fix a blacklisted IP address.
- Implement SMTP relay: If direct sending is prohibited by your ISP, configure your email setup to use an authorized SMTP relay service provided by your host or a third-party email service provider.
- Review authentication records: Ensure your SPF, DKIM, and DMARC records are correctly configured and align with your sending IP addresses and domains. Incorrect SPF records, for example, can lead to 'SPF unauthorized mail is prohibited' errors.
- Consult Google documentation: The error message often links directly to Google's support documentation, which provides valuable context and troubleshooting steps. Refer to the official guidance at Google Mail Help for NotAuthorizedError.
What email marketers say
Email marketers often face challenges when their IP addresses are deemed unauthorized to send mail, leading to bounced emails and deliverability issues. The consensus among marketers experiencing this problem typically points towards issues with their sending IP's reputation or proper authorization by their internet service provider (ISP). Many prioritize checking blocklists and verifying authentication records like SPF, DKIM, and DMARC as initial troubleshooting steps. The key takeaway is frequently the need to collaborate with their ISP or leverage an SMTP relay service rather than attempting direct sending from a non-authorized IP.
Key opinions
- ISP is key: Many marketers emphasize that the ISP is the ultimate authority regarding IP authorization and any related policy blocklist (PBL) listings. Communication with the ISP is seen as mandatory.
- PBL checks: There's a strong recommendation to check if the IP is listed on Spamhaus PBL, as this often aligns with Google's specific error message about unauthorized sending.
- Relay necessity: If an IP is not meant for direct sending, marketers understand the need to use an SMTP relay, which routes email through a third-party server that is authorized to send.
- Authentication validation: Marketers frequently point to SPF, DKIM, and DMARC as crucial elements to check, as misconfigurations can lead to authentication failures and IP authorization issues.
- Sharing IP for diagnosis: Some suggest sharing the problematic IP address can help the community diagnose the specific issue or blocklist listing.
Key considerations
- ISP communication: Even if the ISP claims no policy changes, persistent communication is vital to understand why specific IPs in a pool might suddenly face authorization issues.
- Check all IP types: If using both IPv4 and IPv6, verify if the block affects one or both, and check SPF records for both protocols.
- Reverse DNS (PTR) records: Ensure that your mail server's IP address has a correctly configured Reverse DNS (PTR) record. A mismatch or absence of this record can cause 550 errors and unauthorized flags.
- Bulk sender tickets: For significant email volumes, consider opening a ticket with large email providers like Google if you are a bulk sender, although direct intervention for PBL issues is unlikely from them. For more, refer to our guide on Google Postmaster Tools.
- Email authentication: Marketers must understand that proper email authentication (SPF, DKIM, DMARC) is essential for email deliverability, especially when troubleshooting IP authorization problems. Incorrect SPF configurations can lead to errors such as SPF unauthorized mail is prohibited.
Marketer view
Marketer from Email Geeks states that even though they recently acquired a pool of IPs, only a few are experiencing authorization issues, while others are sending volumes without problems. This suggests a targeted issue rather than a broad infrastructure problem.
Marketer view
Marketer from Email Geeks suggests that omitting the specific IP address when seeking help makes it difficult for others to diagnose the problem. Providing the IP allows for direct blocklist checks and more accurate advice.
What the experts say
Experts in email deliverability consistently highlight the critical role of IP reputation and proper configuration in preventing "IP not authorized" errors. They stress that such issues are almost always tied to ISPs' policies or global anti-spam blacklists (or blocklists) rather than direct recipient server settings. The overarching advice revolves around strict adherence to email best practices, regular monitoring of IP health, and proactive engagement with ISPs when issues arise.
Key opinions
- Policy-based rejections: Experts confirm that PBLs are lists of IPs whose direct mail sending is prohibited by the owning ISP's policy. Receivers, like Google, honor these policies.
- ISP control: It is unequivocally stated that only the ISP can resolve issues related to PBL listings or general IP authorization for their allocated IP ranges.
- Authentication importance: Proper SPF, DKIM, and DMARC setup is paramount for email authorization. Lack of proper alignment is a common cause of such rejections. Our guide on email authentication offers more insights.
- Relay usage: When direct sending is not permitted, using an SMTP relay is the correct technical approach, as it ensures mail is sent via an authorized path.
- Proactive monitoring: Experts advise constant monitoring of sending IPs for blocklist listings and reputation degradation to prevent sudden deliverability outages. Utilize a blocklist checker.
Key considerations
- ISP communication strategy: Prepare specific questions for your ISP, including asking for confirmation on whether the IP is designated for direct mail sending or if it is indeed on a PBL.
- Understand PBL purpose: Recognize that PBLs are not traditional spam blacklists; they are policy lists. This distinction is crucial when discussing with your ISP.
- Review log messages: Analyze the full error message for clues, such as specific reference codes or URLs provided by the recipient server, as these can guide troubleshooting.
- Long-term solutions: If using dedicated IPs, implement consistent sending practices and monitor reputation to prevent future blocklistings and authorization issues. See why your dedicated IPs are blocked.
Expert view
Expert from Email Geeks, Steve589, emphasizes that Google's help article clearly states that the ISP determines if an IP is authorized to send mail. This means senders must work directly with their ISP to resolve such issues.
Expert view
Expert from Email Geeks, Steve589, stresses that senders need to engage their ISP, reinforcing that this is the instructed course of action from Google and other sources.
What the documentation says
Official documentation from major email providers and anti-spam organizations consistently states that an IP address being unauthorized to send email is often a result of either being listed on a policy blocklist or failing email authentication checks. These mechanisms are in place to combat spam and ensure legitimate senders can be verified. The documentation typically advises senders to verify their IP status with relevant blocklist operators, ensure proper authentication protocols (like SPF, DKIM, DMARC) are in place, and, crucially, use an authorized SMTP relay service if direct sending is not permitted by their ISP's policy.
Key findings
- ISP authority: Documentation from Google states that the ISP providing the IP address is responsible for determining whether it is authorized to send mail directly.
- SMTP relay guidance: The common resolution provided is to use an SMTP relay service from the internet service provider, rather than attempting to send directly from a potentially policy-blocked IP.
- Spamhaus PBL relevance: Information suggests that Google (and others) may reject emails from IPs listed in the Spamhaus database, specifically mentioning the PBL as a frequent cause for this type of unauthorized error.
- Authentication checks: Documentation indicates that proper email authentication (SPF, DKIM, DMARC) is essential for mail to be accepted, and failures can result in rejection messages like 'not authorized'.
- Reverse DNS (PTR) importance: Absence or mismatch of a PTR record for the mail server's IP address is a documented reason for 550 errors and unauthorized sender rejections.
Key considerations
- Verify SPF record: Ensure your SPF record correctly lists all IP addresses and hostnames authorized to send emails for your domain. An incorrect or missing SPF record is a common cause of 'SPF fail - not authorized send' errors.
- Check email error codes: The '550-5.7.1' error code is specific and points to sender policy issues. Understanding these codes helps in diagnosing the problem. Documentation often provides a library of such errors.
- ISP communication protocol: Official advice emphasizes that direct engagement with your ISP is the correct route for resolving PBL issues or unauthorized IP status, as external mail providers cannot override these policies.
- Ongoing monitoring: Documentation implicitly encourages continuous monitoring of IP status and deliverability metrics, often suggesting tools like Postmaster Tools.
Technical article
Documentation from Google Mail Help (as referenced in Stack Overflow) states that the ISP determines whether an IP address is authorized to send mail. This means the authority lies with the network provider.
Technical article
Documentation from Prepaid Hoster's FAQ highlights that Google rejects emails from IP addresses listed in the Spamhaus database. This is a measure to prevent spam and unwanted messages, directly causing the "IP not authorized" error.
Related resources
11 resources
Related pages
Why is my IP address blacklisted when sending email, and how can I fix it?
Why is my IP listed on Spamhaus and how do I resolve it?
An in-depth guide to email blocklists
A simple guide to DMARC, SPF, and DKIM
How to fix the 'SPF unauthorized mail is prohibited' error
What causes a 'relaying denied' error when sending emails, and how can I diagnose the issue?
Why Your Emails Are Going to Spam in 2024 and How to Fix It
Boost Email Deliverability Rates: Technical Solutions from Top Performing Senders
Email Deliverability Issues: Getting Your Messages to the Inbox in 2025
What happens when your ip gets blocklisted?
