Why is my IP address not authorized to send email and how do I fix it?
Matthew Whittaker
Co-founder & CTO, Suped
Published 25 May 2025
Updated 16 Aug 2025
8 min read
The error message "The IP you're using to send mail is not authorized to send email directly to our servers" is a common roadblock for many senders. It means the receiving mail server, such as Gmail, has determined that your sending IP address isn't permitted to send mail from your domain directly to them. This can be frustrating, especially when you believe your setup is correct, but it's a security measure designed to combat spam and ensure legitimate email delivery.
This issue often arises due to various underlying factors, ranging from incorrect DNS configurations to policy-based blocklists maintained by ISPs. Understanding the root cause is the first step toward resolving it and ensuring your emails reach their intended recipients without being rejected.
Understanding the "IP not authorized" error
When you encounter the "IP not authorized" message, it typically points to a failure in how your sending IP is perceived by the recipient's mail server. Mail servers perform checks to verify that the sender's IP address is indeed allowed to send email on behalf of the domain it claims to be from. If these checks fail, or if the IP is flagged for policy violations, your email will be rejected. This is a common defense against spam, phishing, and spoofing attempts.
The rejection message often provides clues, such as mentioning an SMTP relay or directing you to a help page. Google's common response, "The IP you're using to send mail is not authorized to send email directly to our servers. Please use the SMTP relay at your service provider instead. Learn more at Google's not authorized error help," explicitly suggests that direct sending from your IP is not allowed by policy.
A primary reason for this type of rejection is when your IP address is a dynamic IP, typically assigned by consumer ISPs, which are not intended for direct mail server communication. ISPs often list these dynamic IP ranges on policy blocklists (or blacklists) to prevent their residential users from running unauthorized mail servers and inadvertently (or intentionally) sending spam.
Common causes of IP authorization issues
Several factors can lead to your IP address being deemed unauthorized to send email. Identifying the specific cause is crucial for a targeted resolution.
A frequent culprit is an improperly configured SPF record. The Sender Policy Framework (SPF) record is a DNS TXT record that specifies which mail servers are authorized to send email on behalf of your domain. If your sending IP address is not included in this record, recipients' servers will reject your emails because they cannot verify its legitimacy. For instance, if your SPF record states only one mail server is allowed to send, but you're sending from a different IP, the authorization check will fail. You can learn more about how to fix an SPF softfail domain if your domain does not designate the IP as a permitted sender.
Another common issue is when your IP address is a dynamic IP, typically assigned by consumer internet service providers. These IPs are generally meant for browsing and personal use, not for running mail servers. Many recipient mail servers, like Google, will reject direct connections from dynamic IP addresses as a spam prevention measure. Your ISP may list these IPs on specific blocklists (also called blacklists), such as Spamhaus PBL (Policy Block List), which designates IP ranges that should not be sending email directly. You can check your IP on the Spamhaus lookup tool directly.
Thirdly, your IP could be listed on a Real-time Blackhole List (RBL) or other DNS-based blocklists (DNSBLs) due to a poor sending reputation. This happens if the IP has been associated with spamming activities, even if it wasn't you who caused the issue. For example, Error 550 often relates to blocklists. You can check if your IP address is listed on a blocklist using a blocklist checker to investigate. These listings indicate to receiving mail servers that emails originating from your IP should be treated with suspicion or outright rejected.
How to fix IP authorization problems
Resolving an IP authorization issue requires a systematic approach, often involving your internet service provider (ISP) and adjustments to your DNS records.
The most common and often simplest solution is to use your ISP's designated SMTP relay server. Instead of sending email directly from your IP, you configure your mail client or server to send emails through your ISP's authenticated SMTP server. These servers are specifically authorized to send email on behalf of their users and are typically whitelisted by major email providers. This bypasses the need for your specific IP to be authorized for direct sending.
If you are certain you need to send directly from your IP, ensure your SPF record correctly includes your sending IP address. An SPF record explicitly tells receiving mail servers which IP addresses are permitted to send email from your domain. If your IP isn't listed, or if the record is configured incorrectly, your emails will be rejected. You can use a free DMARC record generator tool to help with this, and understand how to fix the SPF unauthorized mail is prohibited error.
Direct sending from your IP
Your local server directly connects to the recipient's mail server.
Your IP address needs proper authentication (SPF, DKIM, PTR) and a good reputation to avoid rejections.
Commonly leads to 'IP not authorized' errors if your IP is dynamic or has a poor reputation.
Using an SMTP relay
Your local server sends emails to an intermediary SMTP server provided by your ISP or a dedicated email service.
The relay server then sends the email to the recipient on your behalf. These servers are designed for high deliverability.
Ideal for dynamic IPs or if your own IP's reputation is poor.
If your IP is listed on a blocklist (blacklist), you'll need to request its delisting. For policy blocklists like Spamhaus PBL, delisting requests typically need to go through your ISP, as they own the IP range and are responsible for its policy. For reputation-based blocklists, you might be able to request delisting yourself after addressing the underlying issues that led to the listing. This often involves identifying and stopping the spam source, securing your server, and demonstrating a clean sending history. For more information, you can check out an in-depth guide to email blocklists.
Preventing future IP authorization issues
Maintaining proper email deliverability requires ongoing attention to your sending infrastructure and practices. Proactive measures can help prevent future "IP not authorized" errors.
Always ensure your SPF and DKIM records are correctly set up and remain valid. These authentication methods are fundamental to proving your email's legitimacy and aligning with sender guidelines from major mailbox providers. Regularly review your DNS records to confirm they accurately reflect your current sending infrastructure. Misconfigurations or outdated entries are a common cause of deliverability issues. For more details, refer to a simple guide to DMARC, SPF, and DKIM.
Important reminder on blocklists (blacklists)
Many receiving mail servers subscribe to various email blocklists (also known as blacklists) to filter out spam. If your IP address ends up on one of these lists, even for legitimate sending, it can significantly impact your deliverability. Regularly checking your IP against common blocklists is a proactive step. You can understand more about what happens when your IP gets blocklisted and how to resolve it.
Monitor your email sending reputation closely. Tools like Google Postmaster Tools (for Gmail recipients) provide insights into your spam rate, IP reputation, and domain reputation. High bounce rates, spam complaints, or being listed on blocklists are clear indicators of reputation issues that need immediate attention. A decline in reputation can lead to IP authorization failures. Consider implementing blocklist monitoring as a proactive measure.
Avoid sending large volumes of email from dynamic IP addresses. If you're a business or send marketing/transactional emails, consider using a dedicated email service provider (ESP) or arranging for static, authorized IP addresses with your ISP. ESPs specialize in managing sending infrastructure, IP reputation, and deliverability, taking the burden off your shoulders. They use robust SMTP relays that are designed for high-volume, reliable email delivery.
Views from the trenches
Best practices
Always use your ISP's SMTP relay for sending emails if you have a dynamic IP address. This is the most reliable way to ensure delivery, as these relays are authorized.
Regularly monitor your domain's SPF and DKIM records to ensure they are correctly configured and updated, preventing authentication failures.
If you're a bulk sender, utilize Postmaster Tools offered by mailbox providers to track your reputation and identify issues early.
Common pitfalls
Attempting to send direct email from a dynamic IP address, which is often designated for residential use and automatically blocklisted by ISPs.
Not contacting your ISP when your IP is listed on a policy blocklist like Spamhaus PBL, as they are the only ones who can delist it.
Ignoring reverse DNS (PTR record) configuration, which is essential for proper IP validation by recipient mail servers.
Expert tips
For critical email sending, invest in a dedicated IP address or use a reputable third-party email service provider.
Implement DMARC with a monitoring policy (p=none) to gain visibility into your email authentication failures and unauthorized sending.
Conduct regular deliverability tests to identify potential IP authorization issues before they impact your email campaigns.
Expert view
Expert from Email Geeks says: The “IP not authorized” error often means your IP is on a policy block list, such as Spamhaus PBL. Your ISP sets these policies, so they are the only ones who can resolve it.
May 24, 2023 - Email Geeks
Marketer view
Marketer from Email Geeks says: I once had this issue, and it turned out my ISP had listed my IP on Spamhaus PBL. After contacting them, they clarified their policy and helped me use their SMTP relay.
June 1, 2023 - Email Geeks
Ensuring your email sending authority
Dealing with an "IP address not authorized to send email" error can be challenging, but it's a solvable problem with the right approach. Whether the issue stems from dynamic IP usage, blocklist inclusion (blacklist), or incorrect DNS records, the solutions revolve around proper email authentication and adherence to ISP policies. Prioritizing correct SPF and DKIM configurations, utilizing appropriate SMTP relays, and maintaining a healthy sender reputation are key steps. By proactively managing these aspects, you can ensure your email sending infrastructure is fully authorized, leading to higher deliverability and successful communication.
Gmail, has determined that your sending IP address isn't permitted to send mail from your domain directly to them. This can be frustrating, especially when you believe your setup is correct, but it's a security measure designed to combat spam and ensure legitimate email delivery.
Google, will reject direct connections from dynamic IP addresses as a spam prevention measure. Your ISP may list these IPs on specific blocklists (also called blacklists), such as 
Spamhaus PBL (Policy Block List), which designates IP ranges that should not be sending email directly. You can check your IP on the Spamhaus lookup tool directly.
Spamhaus PBL, delisting requests typically need to go through your ISP, as they own the IP range and are responsible for its policy. For reputation-based blocklists, you might be able to request delisting yourself after addressing the underlying issues that led to the listing. This often involves identifying and stopping the spam source, securing your server, and demonstrating a clean sending history. For more information, you can check out an in-depth guide to email blocklists.
