What does it mean when Free.fr SMTP responses show an IP as blacklisted on Spamhaus PBL even though it's not?

Email marketer from StackOverflow answers by stating that the root cause could be that Free.fr's mail server is misconfigured to check the wrong IP against the PBL, or that their PBL implementation is flawed.

Email marketer from Gmass explains that domain reputation could cause deliverability issues. If one IP has damaged reputation on the PBL or other blocklists, this might impact all IPs on the same range. It might be useful to contact the IP provider to solve these problems together.

Email marketer from EmailDudes Forum explains that the fastest resolution is to contact Free.fr support with a detailed report, including the sending IP, the timestamp of the error, and a copy of the SMTP conversation.

Email marketer from Email Geeks shares that the SMTP response from free.fr shows an IP as blacklisted on Spamhaus PBL, even though the IP is not actually listed on Spamhaus. He also notes that the IPs listed in the SMTP response are indeed sending IPs and that Free postmaster said they had a local issue and fixed it.

Email marketer from Talos Intelligence explains the importance of IP and domain reputation and that even if an IP isn't directly listed, poor reputation scores can trigger stricter filtering rules by receiving mail servers, leading to rejections that might be mistakenly attributed to specific blocklists.

Email marketer from Reddit explains that Free.fr has been known to have issues with their Spamhaus PBL lookups, leading to false positives. They suggest contacting Free.fr support directly to report the issue, as it's likely an error on their end.

Email marketer from EmailGeeks Forum shares that misconfiguration of Free.fr's mail servers or outdated DNS records could be causing the false positives. Suggests checking the sending IP's reputation on other blocklists as well.

Email marketer from MXToolbox explains that using tools available on MXToolbox.com could help diagnose the issue by running blacklist checks, SMTP tests, and DNS lookups to identify if the problem is originating from Free.fr or from the sender's infrastructure.

Email marketer from Mailhardener.com shares that SMTP bounce messages are often non-standardized. They note that while the 'Spamhaus PBL' mention provides a clue, the 'unable to connect to MX servers' part suggests a network connectivity issue between the sending server and Free.fr's MX servers, and is likely unrelated to the PBL itself.

Expert from Email Geeks says that the “Invalid response code” means that Free broke something and that it's not a spamhaus issue.

Expert from Word to the Wise (Laura Atkins) explains that SMTP error messages can be misleading or inaccurate. It's important to understand the context and not rely solely on the text of the error to diagnose the problem.

Expert from Email Geeks explains that PBL is a list of consumer IP addresses that shouldn’t be originating mail.

Expert from Spam Resource (referencing Halvar Flake) explains that false positives can occur due to issues with reputation scoring systems. Suggests checking the IP against multiple reputation services to get a more complete picture.

Documentation from Microsoft shares the potential for blocklist errors is always present and that it's key to check the raw message headers for specific error messages to understand the context of the issue better.

Documentation from Dnsrecords.io explains the steps involved in performing a DNS lookup to verify whether an IP is listed on the Spamhaus PBL, and that checking against multiple DNSBL lookup tools is key to determine if this is a genuine block or a Free.fr issue.

Documentation from IETF answers question explaining that SMTP Enhanced Status Codes, where implemented correctly, offer more specific information on the reason for mail delivery failures. The '499' code suggests that Free.fr is using a non-standard code, indicating a custom error that needs to be understood in the context of their specific implementation.

Documentation from SendGrid.com shares the email deliverability troubleshooting that when receiving an error related to a blocklist, and after verifying that the IP is not actually on that list, contacting the receiving mail server's support team to investigate the issue is the appropriate next step.

Documentation from Spamhaus.org explains that the PBL (Policy Block List) is a DNSBL database of end-user IP address ranges which should not be delivering unauthenticated email to mail servers. It is designed to block spam from hijacked or infected end-user machines.

Documentation from RFC-Editor.org explains that SMTP server responses beginning with '4' indicate a transient failure. The server should be retried by the client. It also defines the codes that relate to connection issues and syntax errors. An invalid response code such as that given by Free.fr implies non-compliance with protocol standards.

Documentation from Postmaster.google.com answers the process by saying that although the bounce message mentions Spamhaus, Google says to contact Free.fr support directly and provide them with the full bounce message and any relevant logs for investigation.