Domain Name Blocked List. The Domain Block List DBL The Spamhaus DBL is a list of domain names with poor reputations. If your mail server has been blacklisted some email you send may not be delivered.
To use an existing list as your blocked sender list under Available lists click the list name. Add the domain you wish to block or allow to the Always block and Never Block respectively. If your mail server has been blacklisted some email you send may not be delivered.
Select Settings View all Outlook settings.
The Domain Health Check will execute hundreds of domainemailnetwork performance tests to make sure all of your systems are online and performing optimally. Domains you wish to block specifically are added to the Always block list while domains you wish to allow access are added to the Never block list. If your domain is blacklisted it means that you get into the spam list and domains reputation has dropped. Most mail server software can be configured to check one or more of such lists - typically rejecting or flagging messages.