NOTE: When connecting to the database, Spotlight looks at the SQLNet.ora file "Names.directory_path " parameter. This usually shows [Tnsnames, ONames, HOST, or LDAP, etc].
NAMES.DIRECTORY_PATH= (TNSNAMES, ONAMES)
The SQLNet.ora file is located under the following path by default on the client machine.
To resolve this issue, please edit the SQLNet.ora file and move your primary SQL*Net method to the very front of the "Names.directory_path " parameter list . This will be "Tnsnames.ora" or "ONames" depending on which method used in your environment.