I followed this blog post by Mónica Godoy to connect a non Oracle DB using Apex
https://blogs.oracle.com/apex/post/connecting-your-apex-apps-to-non-oracle-databases-with-oracle-autonomous-database
I have a PostgrSQL DB running on Azure. So the root cert of Azure should be in the OCI wallet. I am using a always free DB for a POC to see it it will work.
I get this error
ORA-28500: connection from ORACLE to a non-Oracle system returned this message:
[DataDirect][ODBC PostgreSQL Wire Protocol driver]SSL certificate chain could be built up using the untrusted certificates but the root could not be found locally. {HY000,NativeErr = 7551}[DataDirect][ODBC PostgreSQL Wire Protocol driver]SSL Handshake Failure reason [error:0A000086:SSL routines::certificate verify failed]. {08001,NativeErr = 7570}
ORA-02063: preceding 2 lines from AZURE_DBLINK
28500. 00000 - "connection from ORACLE to a non-Oracle system returned this message:"
*Cause: The cause is explained in the forwarded message.
*Action: See the non-Oracle system's documentation of the forwarded
message.
Error at Line: 22 Column: 18