IP-NO-PTR
No reverse DNS for the address
What it means
Receivers check PTR records on connecting servers; missing reverse DNS is a strong spam signal.
How to fix it
- 1Ask the provider that owns the address block to publish a PTR matching the server hostname.
Re-check after the change
DNS changes can take up to the record's TTL to be seen; use Re-run on the result page to bypass our 10-minute cache.