DNSBLs (DNS-based blacklists) are real-time lookups against curated lists of known mail abusers. Listing on a major DNSBL typically results in inbound rejection at receiving servers; even minor DNSBL hits can reduce inbox placement.
The hits above show which DNSBL zones return a positive response for this domain (or its mail-sending IPs). Each zone has its own listing methodology and reputation; some are aggressive (fast to list, slow to delist), others are conservative.
A clean result is the goal — zero listings across all checked zones. If listed, follow the specific zones delisting procedure (linked from the zone name). Check whether your sending volume, list-hygiene practices, or recently-rotated infrastructure triggered the listing; address the root cause before requesting delisting.