The following reasons might cause a connection attempt to an ODBC data source to fail:
The schema holder is not connected.
The OpenEdge or ODBC-required environment variables are not set correctly when using the DataServer and a broker. For environment variable information, see Configuring the DataServer
The data-source is not registered properly for ODBC client connectivity.
You have an outdated version of an ODBC DLL; for example, ODBC16.DLL, which runs on 16-bit machines only. This prevents OpenEdge from accessing the data source, though you might still be able to access the data source through your ODBC driver using another product, such as MS Query.
The data source has not been started or is not running correctly. Use the data-source utilities to check the status of the data source and the ability to connect to it.