554 5.7.1 Service unavailable

If you see an error like “554 5.7.1 Service unavailable; Client host [xxx.xxx.xxx.xxx] blocked you may be infected” this error message is displayed because the internet gateway (identified by the public IP address XXX.XXX.XXX.XXX) that you were using when sending your email is blacklisted by Spamhaus Project due to a high probability of spam, as you can see on the following report:

https://www.spamhaus.org/query/ip/XXX.XXX.XXX.XXX

Consequently the sending of emails from that IP address has been temporarily blocked.

Spamhaus Project is a tool used by Gandi to assess the trustworthiness of emails that travel through our platform. Put simply, Spamhaus Project allows us to know if the IP address used when sending your email is considered as being reliable or not. In your case, your sending is not deemed reliable, and the transmission of email is therefore blocked in order to avoid any risk of the sending of spam to others.

In accordance with Gandi’s values and commitments, including binding contractual provisions, made with regard to the GandiMail service, the use of this service relies at no point on the study of your private communications’ content and only aims at enhancing our customers and platform’s security by mitigating service abuse and spam risks.

Here is some useful information for

  1. Requesting the unblocking of the public IP address by Spamhaus Project

The public IP address is blocklisted. You or your IT team therefore needs to follow the process as outlined on the Spamhaus Project website.

To do this, click on the “CBL” link present in the report on the page presented in the above link. After the captcha verification, you will see a detailed report for this public IP address, and the reasons for it being blocked. This information will be useful for identifying the source of the potential network internal breaches and to correct them.

Once these problems have been corrected, you will have the opportunity to request the delisting of the public IP address (via the “Remove” button on the bottom of the page).

Please note that if the security issues are not addressed and you still use the same setup and configuration (including the IP address), you will find yourself in the same situation a few days later.

  1. Use a temporary solution:
  • You can use one of our webmails to send/receive email: (https://sogo3.gandi.net/ or https://webmail.gandi.net/) or
  • You can configure your email application (Outlook, Mail, Thunderbird, etc) so that it uses the SMTP (outgoing mail server) of your internet provider to send emails. Here is a link that can help you know what the SMTP servers are of the major internet providers (you will need to use the one that you use for your internet connection):

http://ccm.net/faq/9166-smtp-imap-and-pop-server-settings-for-major-isps