Scan your mail server IP or domain against 13+ major email blacklists including Spamhaus, SpamCop, and Barracuda.
An email blacklist (DNSBL) is a real-time list of IP addresses or domains that have been reported for sending spam. Mail servers check these lists to decide whether to accept, reject, or quarantine incoming email.
Each blacklist has its own delisting process. Generally, fix the issue that caused the listing (open relay, compromised account, spam complaints), then submit a delisting request on the blacklist provider's website.
Common reasons include: sending spam or bulk unsolicited email, having a compromised email account, running an open relay, being on a shared IP with a spammer, or having poor email authentication (missing SPF/DKIM/DMARC).