How to fix the Oracle error ORA-28557: unknown string for database link to non-Oracle system?

In this post, you’ll learn more about the Oracle ErrorORA-28557: unknown string for database link to non-Oracle system with the details on why you receive this error and the possible solution to fix it.

Oracle Error Description

ORA-28557: unknown string for database link to non-Oracle system

Reason for the Error ORA-28557: unknown string for database link to non-Oracle system

When attempting to connect to a non-Oracle system through a Heterogeneous Services database link, the agent supporting this non-Oracle system failed to return FDS_CLASS_NAME and/or FDS_INST_NAME. ORACLE requires these names to configure the heterogeneous database link.

How to fix the Error ORA-28557: unknown string for database link to non-Oracle system ?

You can fix this error in Oracle by following the below steps

Contact the DBA to check setup of the connection and the Heterogeneous Services agent.