What is the solution of the ORA-03121 error?
What is the solution of the error "ORA-03121: No interface driver connected. Function not performed"?
First, check to see that SQL Net is installed on the client machine. If SQL Net is installed, ensure that the connect string used by the program is in the tnsnames.ora file on the client. For example, check to see if your program can connect with:
hr/[email protected]Ensure that the service name ORATST01 is defined in the tnsnames.ora file. This file can usually be found in the network/admin subdirectory where the Oracle client software is installed.