DNS_ERROR_CNAME_COLLISION - 9709 (0x25ED)
A CNAME record already exists for given name.
Updated: Feb 21, 2026
Technical Meaning
This error indicates that a CNAME (Canonical Name) record already exists for the specified domain name. A CNAME record is used to map one fully qualified domain name (FQDN) to another FQDN, and it cannot coexist with other types of DNS records for the same name.
Error Details
The error code DNS_ERROR_CNAME_COLLISION signifies that an attempt was made to add or modify a CNAME record in the DNS database, but the specified domain name already has a CNAME record associated with it. This can occur during operations such as adding a new CNAME entry or updating existing records.
Common Causes
- Invalid Parameter Values: The operation attempted to create or update a CNAME record for an FQDN that already has another type of DNS record (e.g., A, MX).
- Incorrect Object Type: The operation was intended for a different type of DNS record and thus encountered a conflict with the existing CNAME.
Real-World Context
This error can occur in various scenarios where DNS records are managed or updated. For example, it might happen during the configuration of domain nameservers or when integrating new services that require specific DNS mappings.
Is This Error Critical?
The criticality of this error depends on the context and the intended operation. If a CNAME record is being added to an FQDN that already has another type of DNS record, it may indicate a misconfiguration or incorrect planning in the domain name management process. However, if the intention was to update or replace an existing CNAME, the error might not be critical.
How to Diagnose
- Review Operation Context: Ensure that the operation aligns with the intended configuration of DNS records.
- Validate Parameters: Verify that the parameters passed during the operation are correct and match the expected values for a CNAME record.
- Confirm Object Types: Check if the FQDN in question already has another type of DNS record. If so, determine whether the operation should be allowed or if it needs to be adjusted.
How to Resolve
- Correct Parameter Usage: Ensure that all parameters are correctly specified for a CNAME record. This includes the target name and any other required fields.
- Adjust Operation Context: If the intention was to update an existing CNAME, ensure that the operation is performed in the correct context. If it was intended to add a new CNAME, consider whether this is necessary or if another type of DNS record should be used instead.
Developer Notes
When working with DNS records, developers must carefully manage CNAME entries to avoid conflicts. Ensure that all operations are well-planned and tested before deployment to prevent such errors from occurring.
Related Errors
FAQ
Q: What does DNS_ERROR_CNAME_COLLISION mean?
A: It indicates that a CNAME record already exists for the specified domain name.
Q: How can I prevent this error?
A: Ensure that all operations align with the intended configuration and verify parameters before performing any changes to DNS records.
Summary
The DNS_ERROR_CNAME_COLLISION error code is specific to situations where a CNAME record already exists for the specified domain name. This error requires careful management of DNS records to avoid conflicts and ensure proper operation.