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Email refused because of a blocklist

Why Mailyoto refuses email from servers and domains on public blocklists, and how the sender gets delisted.

Updated 27 October 2026

Someone tells you their email to your alias bounced, and the bounce names Spamhaus or SpamCop. The bounce holds one of these responses from Mailyoto.

When a blocklist lists the sending server’s address:

550 5.7.1 We refuse mail from {ip} while Spamhaus lists it. Details: https://check.spamhaus.org/results/?query={ip}

When SpamCop lists the address, the response names SpamCop, and its link opens https://www.spamcop.net/bl.shtml?{ip}.

When Spamhaus lists the sender’s domain:

550 5.7.1 We refuse mail from {domain} while Spamhaus lists it. Details: https://check.spamhaus.org/results/?query={domain}

Why it happens#

Spamhaus and SpamCop publish lists of server addresses and domains that send spam. Mailyoto checks every incoming connection against them:

  • the address of the server that connects, against Spamhaus ZEN, then SpamCop
  • the domain in the sender’s From address, against the Spamhaus domain list

Forwarding mail from a listed source would harm the reputation of Mailyoto’s sending servers, and with it the delivery of everyone’s email. There is no allow list for a sender, on any plan.

A refusal for a listed server address happens before the message arrives. It has no entry in your logs. A refusal for a listed domain shows in your logs as Failed.

Fix it#

The listing belongs to the sender, and the sender fixes it. Send them this list.

  1. The response holds a link to the blocklist’s own lookup page. It says why the blocklist lists the address or domain.

  2. Fix the cause#

    A listing usually follows spam sent from that server or domain, often from a compromised account or a shared server. When the sender uses an email provider, the provider owns the server and fixes it.

  3. Request removal#

    The lookup page explains how to ask for delisting. Some listings clear on their own once the spam stops.

  4. Send the email again#

    Once the lookup page shows no listing, the sender sends the message again.

Confirm it worked#

Open Logs and search for the sender’s address. A new entry for the message, with Delivered as its status, means it reached your inbox.

The sender's provider says the listing is not theirs

Ask the sender to look up the address in the bounce, not their domain. A blocklist can list a shared server because of another customer of the same provider.

I send through Mailyoto from home and get this refusal

Spamhaus keeps a list of home and mobile internet addresses that are not meant to send email directly. Mailyoto doesn’t refuse you for that listing when you sign in with an SMTP credential. If you still get the response, your connection’s address is on another list. Your internet provider can tell you why.