A listing means receiving servers reject or filter your mail.
CHECKING
Use an online blacklist lookup against your domain and the sending address. It shows which lists you appear on.
FIX THE CAUSE FIRST
Delisting while the problem continues is refused, and repeated requests lengthen the process.
- Change every mailbox password on the account.
- Look for a script or form being abused to send mail.
- Check for forwarding rules you did not create.
- Confirm SPF, DKIM and DMARC are correct.
- Use Track Delivery to confirm sending has stopped.
REQUESTING REMOVAL
Each list has its own process, linked from the lookup results. Some delist automatically after a clean period; others need a form explaining what happened and what you fixed.
IF THE SERVER'S SHARED ADDRESS IS LISTED
That is ours to handle. Open a ticket. Anything specific to your domain is yours.
REBUILDING REPUTATION
Send modestly for a few weeks. Reputation recovers through clean sending history, not through a request.