Emails rejected: your IP address is blacklisted

Sometimes emails fail with an error mentioning a blacklist, blocklist, RBL or listed IP. This usually has nothing to do with your email account: it’s about the internet connection you’re sending from.

Why it happens

Your internet service provider (ISP) gives your office or home connection an IP address. If spam is sent from that IP, for example by a computer on your network infected with malware, or by a previous user of the same IP, it gets listed on public blacklists. Mail servers then refuse email sent from that connection.

Check your IP

1. Find your public IP address by searching “what is my IP”.
2. Check it with a tool such as MXToolbox Blacklist Check.

Fix it

1. Scan every computer on your network for viruses and malware, and change the passwords of any compromised email accounts.
2. Contact your ISP (e.g. BTC, Mascom, Orange or your fibre provider). Tell them your IP is blacklisted and ask them to delist it or give you a new one.
3. Request removal from the blacklist sites that list you. Most have a delisting form.

Workaround while you wait

• Send from webmail. It sends from our servers, not your connection.
• Or send from a different network, such as your phone’s mobile data.