Help Center/ DataArts Studio/ FAQs/ DataArts Migration (CDM Jobs)/ What Should I Do If the Mapping Between a Domain Name in DNS and an IP Address Has Changed but Does Not Take Effect in CDN?
Updated on 2026-06-25 GMT+08:00
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What Should I Do If the Mapping Between a Domain Name in DNS and an IP Address Has Changed but Does Not Take Effect in CDN?

Symptom

During the configuration of a data source connection in CDM, the following error is reported for the data source connectivity check: "Failed to execute jdbc operation, Cause : [CORE_0021:Can't connect to server. Cause : [The connection attempt failed.]] (Cdm.0989)."

Possible Causes

Java processes provide a DNS cache that is located in a Java virtual machine (JVM). The cache improves the performance of domain name resolution and avoids repeated query requests to the DNS server. For security hardening purposes, Java Security Manager is enabled for CDM by default, so DNS records are permanently cached.

Solution

Restart the CDM cluster. The system will automatically clear the DNS cache.