Linked Server to Oracle error ORA-01804
To test Linked Server connectivity, first reboot, and then test OleDb connectivity with 64-bit PowerShell.  EG
PS C:\&gt; $con = new-object system.data.oledb.oledbconnection(&quot;provider=OraOledb.Oracle;data source=N'ORACLE_SERVER;user id=xxxxxxx;password=xxxxxxx&quot;)
PS C:\&gt; $con.Open()