The error *‘ORA-12154: TNS:could not resolve the connect identifier specified’* means that the Oracle service as specified is not listed in '*tnsnames.ora*'. As you have mentioned that you are able to connect via other clients but not on the Virtual DataPort Administration tool, one reason could be that it is using '*tnsnames.ora*' from the wrong *ORACLE_HOME*.
If you wish to connect to Oracle E-business Suite, I would strongly recommend to connect via JDBC driver. The reason is that in Virtual DataPort, queries involving a JDBC data source run faster than if they involve an ODBC data source, even if the underlying source is the same.
You can refer to the [JDBC Sources](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/creating_data_sources_and_base_views/jdbc_sources/jdbc_sources) and [Supported JDBC Data Sources](https://community.denodo.com/docs/html/browse/7.0/vdp/administration/appendix/supported_jdbc_data_sources/supported_jdbc_data_sources) section of the Virtual DataPort Administration Guide for more information.
Hope this helps!