How to resolve Gmail PTR record error when using Cloudflare?
Matthew Whittaker
Co-founder & CTO, Suped
Published 21 Jun 2025
Updated 16 Aug 2025
10 min read
Dealing with email delivery issues can be incredibly frustrating, especially when the error messages seem to contradict what you know about your setup. One common scenario I see is when emails sent to Gmail addresses bounce back with a PTR record error, even when tools like MXtoolbox confirm that a PTR record exists. This often happens when Cloudflare is managing your domain's DNS. The key is understanding how PTR records work and how Cloudflare's proxying affects email sending. Let's dive in to diagnose and resolve this issue.
Many businesses use web forms or internal applications that send simple, one-way emails, such as contact form submissions or notifications. These often rely on the server's own mail agent, like Postfix, to send mail directly. If your website is behind Cloudflare's proxy, it can create a conflict that wasn't present before, leading to delivery failures that seem to come out of nowhere.
My goal is to walk you through the specifics of PTR records, explain why Cloudflare can complicate things for email, and provide actionable solutions to ensure your messages reach the inbox. We'll explore the common reasons for the error and the most effective ways to restore your email deliverability.
Understanding PTR records and reverse DNS
A PTR record, also known as a Pointer Record or Reverse DNS record, performs the opposite function of an A record. While an A record maps a domain name to an IP address, a PTR record maps an IP address back to a domain name. This reverse lookup is crucial for email deliverability because major mail providers, especially Google, use it as a spam prevention measure.
When your mail server sends an email, the recipient's mail server performs several checks to verify its authenticity. One of these is a reverse DNS lookup. It takes the sending IP address, queries the DNS for its PTR record, and then performs a forward lookup (A record) on the resulting hostname. If the hostname from the PTR record doesn't resolve back to the original sending IP, or if there's no PTR record at all, it raises a red flag.
This process, known as Forward-Confirmed Reverse DNS (FCRDNS), helps ensure that the sending server is legitimate and not a spambot or malicious entity. Without a correctly configured PTR record, your emails are much more likely to be rejected or sent to the spam folder, even if other authentication methods like SPF and DKIM are in place.
It's important to understand that PTR records are managed by the entity that owns the IP address block, typically your internet service provider (ISP), hosting provider, or cloud service provider. Cloudflare, while handling your domain's authoritative DNS, does not own your server's IP address and therefore cannot directly set or modify its PTR record.
A record
Function: Maps a domain name (e.g., yourdomain.com) to an IP address (e.g., 192.0.2.1).
Management: Configured in your domain's authoritative DNS (like Cloudflare).
Purpose: Directs web traffic to your server, enables website access.
The Cloudflare conundrum
Here's where the problem often arises when Cloudflare is in the mix. Cloudflare's primary function is to act as a proxy for your web traffic, sitting between your visitors and your origin server. When you proxy a DNS record (indicated by an orange cloud in Cloudflare), the A record for your domain or subdomain points to a Cloudflare IP address, not your actual server's IP. This is excellent for security and performance on the web side.
However, email does not typically route through Cloudflare's proxy. When your server sends an email, it sends it directly from its origin IP address. Gmail (and other mailbox providers) will then perform a PTR lookup on that origin IP. If the PTR record for your origin IP points to a hostname that then, in turn, resolves back to a Cloudflare IP (because your A record is proxied), there's a mismatch. This inconsistency is precisely what Gmail's 550-5.7.25 error message refers to.
This situation can lead to the illusion that Cloudflare is blocking or interfering with your PTR record, when in reality, it's the nature of DNS resolution combined with Cloudflare's proxying that creates the perceived problem. Your hosting provider (or ISP) must set the PTR record for your server's IP address. Cloudflare manages your domain's DNS, not the reverse DNS for your server's IP.
Diagnosing the Gmail PTR error
The Gmail bounce message typically provides a clear indicator of the problem. You might see something like: "550-5.7.25 The IP address sending this message does not have a PTR record setup. As a policy, Gmail does not accept messages from IPs with missing PTR records."
This error means that Gmail performed a reverse DNS lookup on your sending IP and either found no PTR record or found one that didn't properly resolve back to your sending IP. While tools like MXtoolbox might show a PTR record, Gmail's stricter FCRDNS check is the one failing.
To confirm the issue, you can perform a reverse DNS lookup using a command-line tool. For example, on Linux or macOS, you can use dig -x [your_server_ip]. The result should be a hostname. Then, perform a forward lookup on that hostname using dig [hostname]. The IP address returned by the forward lookup must match your original sending IP. If it points to a Cloudflare IP, or any other IP that isn't your sending server, this is your culprit.
This particular 550-5.7.25 error is specifically related to Gmail's policy on email authentication. You can find more details on their official guidelines for bulk senders, which explicitly state the requirement for valid PTR records. For more information, please visit Gmail's authentication requirements page.
Solutions for the Gmail PTR error with Cloudflare
Resolving the Gmail PTR record error when using Cloudflare primarily involves ensuring that your email sending mechanism bypasses the proxy or is correctly configured to maintain FCRDNS. Here are the most effective solutions:
Solution 1: use a dedicated smtp relay service
This is often the most straightforward and recommended solution, especially if your server only sends transactional or notification emails. Instead of sending emails directly from your web server, you configure your application (e.g., your WordPress site or custom application) to relay emails through a specialized SMTP service. These services are designed for email delivery and properly manage their IP addresses, including PTR records, SPF, and DKIM.
Using a dedicated SMTP relay service also helps improve your overall email deliverability by taking the burden of IP reputation management off your shoulders. They handle the complexities of maintaining good sender reputation, monitoring blocklists (or blacklists), and ensuring compliance with major mailbox providers' requirements, including Outlook and Yahoo, among others.
Solution 2: configure your hosting provider's PTR record
If you absolutely must send directly from your server (e.g., you're running your own mail server, not just a web form), you need to contact your hosting provider or ISP to set the PTR record for your server's IP address. This is usually done through their control panel or by submitting a support request. The PTR record should point to a hostname (e.g., mail.yourdomain.com) that, when looked up via an A record, resolves back to your server's exact sending IP address.
Crucially, ensure that the A record for this hostname (e.g., mail.yourdomain.com) in your Cloudflare DNS is set to DNS-only (gray cloud), not proxied (orange cloud). This allows Gmail to correctly perform the FCRDNS check directly with your server's IP address, bypassing any Cloudflare IPs. Remember, Cloudflare does not set PTR records.
Solution 3: complete your email authentication
While resolving the PTR issue is critical, it's part of a larger picture of email deliverability. To ensure your emails consistently reach the inbox, especially with Gmail's and Yahoo's latest requirements, you must implement SPF, DKIM, and DMARC. These records work together to verify the sender's identity and prevent spoofing. Properly configured, they significantly boost your sender reputation and inbox placement.
You can troubleshoot SPF failures and address DMARC verification issues to further fortify your email setup. Neglecting these can still lead to delivery problems, even with a perfect PTR record.
Sending from own server (proxied)
Scenario: Your web server (behind Cloudflare's proxy) attempts to send email directly using its origin IP.
PTR Lookup:Gmail queries the PTR for your origin IP, then tries a forward lookup for the PTR's hostname. If that hostname points to a Cloudflare IP (due to proxying), it fails FCRDNS.
Result: Emails are rejected with a PTR error, leading to bounce messages.
Sending via an SMTP relay service
Scenario: Your application sends emails via a third-party SMTP provider (e.g., Mailgun, Postmark).
PTR Lookup:Gmail performs PTR lookup on the SMTP provider's IP, which is correctly configured for email sending.
Result: Emails are successfully delivered, avoiding PTR issues and improving deliverability.
Views from the trenches
The problem of PTR record issues with Cloudflare and Gmail is a common point of discussion among email deliverability professionals and marketers alike. Here are some insights and practical advice gathered from various online communities.
Best practices
Always use a dedicated SMTP service for sending transactional and marketing emails to avoid IP reputation issues and simplify DNS management.
Ensure that any DNS records related to email (like MX, SPF, DKIM) are correctly configured as DNS-only in Cloudflare to prevent proxying interference.
Regularly monitor your domain and IP for blocklist listings and maintain a healthy sender reputation, regardless of your DNS setup.
Implement SPF, DKIM, and DMARC for all sending domains to meet modern email authentication requirements and improve deliverability.
Common pitfalls
Attempting to set PTR records directly within Cloudflare, which is not possible as Cloudflare does not own your IP address block.
Sending emails directly from a server whose IP address is proxied by Cloudflare, leading to FCRDNS mismatches and delivery failures to Gmail.
Neglecting to implement all major email authentication protocols (SPF, DKIM, DMARC), which are increasingly critical for inbox placement.
Assuming that a visible PTR record is sufficient, without verifying the forward-confirmed reverse DNS (FCRDNS) consistency.
Expert tips
Leverage Google Postmaster Tools to gain insights into your Gmail deliverability performance and identify authentication issues.
If your server requires Cloudflare for web security (like DDoS protection), use an external SMTP relay for email to separate concerns.
For specific applications needing to 'plunk' emails into a Gmail inbox, consider exploring the Gmail API or an SMTP relay configured for that purpose.
Remember that while one blacklist (like UCEPROTECTL3) might be ignorable by some, persistent listing on others can severely impact deliverability.
Marketer view
Marketer from Email Geeks says they encountered a PTR record error from Google, even though MXtoolbox confirmed the record was present. The issue arose after moving to Cloudflare for web form email sending.
2021-09-07 - Email Geeks
Expert view
Expert from Email Geeks says that PTR records are set by the IP block owner, not Cloudflare, and that Cloudflare's proxying can lead to a forward and reverse lookup mismatch for the sending IP.
2021-09-07 - Email Geeks
Restoring your email deliverability
The Gmail PTR record error when using Cloudflare is a common hurdle, but one that is entirely resolvable. The core issue isn't that Cloudflare prevents PTR records from existing, but rather that its proxying can disrupt the critical Forward-Confirmed Reverse DNS check performed by major mailbox providers. Since Cloudflare doesn't own your server's IP, it cannot manage its PTR record, which must be set by your hosting provider.
The most reliable path to resolution is usually to integrate a dedicated SMTP relay service for your outgoing emails. This approach offloads the complexities of email deliverability, including PTR management and IP reputation, to specialists. If direct sending from your server is unavoidable, meticulous configuration of your PTR record with your hosting provider and ensuring DNS-only records in Cloudflare for mail-related entries are essential.
Always remember that a robust email setup goes beyond just PTR records. SPF, DKIM, and DMARC are equally vital components of a healthy email ecosystem, working in tandem to build and maintain trust with recipient servers and ensure your legitimate messages land in the inbox.
Gmail addresses bounce back with a PTR record error, even when tools like MXtoolbox confirm that a PTR record exists. This often happens when 
Cloudflare is managing your domain's DNS. The key is understanding how PTR records work and how Cloudflare's proxying affects email sending. Let's dive in to diagnose and resolve this issue.
Google, use it as a spam prevention measure.
Outlook and 
Yahoo, among others.
