You are running a server / vserver and one or more IP addresses that are configured for your server are listed on a blacklist for spam avoidance.
Unfortunately, it sometimes happens that IP's or networks on blacklists land. In connection with badly configured mailserver on the receiver side, which only rely on a blacklist (keyword "scoring") is then annoying.
You must solve two tasks in order to be able to send again in the short term and 2.) to be able to reuse your IP address in the long term.
To solve the problem, proceed as follows:
- Install a workaround with a new IP: Create a new IP address from the MCC and temporarily send your emails with the new IP address. A corresponding config of the e-mailer is necessary for this to send with the new IP. Ensure correct RDNS and generally correct config and avoid spam over this IP.
- Leave the entry for your IP address removed from the list. This is partly somewhat tedious, but will be successful anyway. Contact the Blacklist operator and tell him that you are the administrator of the IP address and that your host does not send spam.
- The removal / delisting of blacklists may take up to several weeks or even months. Also there is partly no feedback from the Blacklistbetreiber. Stubbornness is at the top!