If you are experiencing problems delivering emails to other providers, a blacklist entry for your domain or the server you are using may be the cause. There are a number of free tools available to check whether your email address, domain, server or IP address is on a blacklist.
Checking spam lists/blacklists
If your email could not be delivered, you will usually receive an error message (bounce message) from the server to which you sent the email. This message will state the reason for the delivery error. These are either given as an error code or as text - often a combination of both. If you are on a blacklist, the specific blacklist is often stated directly in the message.
As there are a large number of blacklist providers whose aim is to ensure that email traffic is as free from spam and fraud as possible, there are correspondingly many portals where you can check your details.
Some blacklist providers may also give you information on why your domain, IP address or server has been blocked, although the extent to which they disclose this information varies from provider to provider.
We have provided further information on DNSBL lists - what they are and how they work - in our blog (DNSBL Lists: What They Are and How to Check Them).
Here, we would like to introduce you to the most common tools and blacklists.
Multi-RBL Check
With the Multi-RBL Check, you can quickly and easily check against many different blacklist providers:
https://multirbl.valli.org/
https://mxtoolbox.com/blacklists.aspx
Single-RBL Check
These check pages provide manufacturer-specific checks, which may help you narrow down the problem further.
AOL / Yahoo Blacklist
- https://senders.yahooinc.com/contact - Offers the option to request unblocking
Cloudmark CSI Blacklist
- https://csi.cloudmark.com/en/reset/ - Offers the option to request unblocking
dnsbl.spfbl.net
- https://spfbl.net/en/delist/ - Offers the option to request unblocking
Microsoft / Office 365 / Outlook.com
- https://sender.office.com/ - Offers the option to request unblocking
Trendmicro
- https://www.ers.trendmicro.com/ - Offers the option to request unblocking
Symantec Blacklist
- https://ipremoval.sms.symantec.com/ - Offers the option to request unblocking