ORA-12154: TNS:could not resolve the connect identifier specified
 *Cause:  A connection to a database or other service was requested using
 a connect identifier, and the connect identifier specified could not
 be resolved into a connect descriptor using one of the naming methods
 configured. For example, if the type of connect identifier used was a
 net service name then the net service name could not be found in a
 naming method repository, or the repository could not be
 located or reached.
 *Action:
   - If you are using local naming (TNSNAMES.ORA file):
      - Make sure that "TNSNAMES" is listed as one of the values of the
        NAMES.DIRECTORY_PATH parameter in the Oracle Net profile
        (SQLNET.ORA)
      - Verify that a TNSNAMES.ORA file exists and is in the proper
        directory and is accessible.
      - Check that the net service name used as the connect identifier
        exists in the TNSNAMES.ORA file.
      - Make sure there are no syntax errors anywhere in the TNSNAMES.ORA
        file.  Look for unmatched parentheses or stray characters. Errors
        in a TNSNAMES.ORA file may make it unusable.
   - If you are using directory naming:
      - Verify that "LDAP" is listed as one of the values of the
        NAMES.DIRETORY_PATH parameter in the Oracle Net profile
        (SQLNET.ORA).
      - Verify that the LDAP directory server is up and that it is
        accessible.
      - Verify that the net service name or database name used as the
        connect identifier is configured in the directory.
      - Verify that the default context being used is correct by
        specifying a fully qualified net service name or a full LDAP DN
        as the connect identifier
   - If you are using easy connect naming:
      - Verify that "EZCONNECT" is listed as one of the values of the
        NAMES.DIRETORY_PATH parameter in the Oracle Net profile
        (SQLNET.ORA).
      - Make sure the host, port and service name specified
        are correct.
      - Try enclosing the connect identifier in quote marks.

   See the Oracle Net Services Administrators Guide or the Oracle
   operating system specific guide for more information on naming.

tnsnames.ora Network Configuration File: J:\ORACEL21C_DATABASE\homes\OraDB21Home3\NETWORK\ADMIN\tnsnames.ora

sqlnet.ora Network Configuration File: J:\ORACEL21C_DATABASE\homes\OraDB21Home3\NETWORK\ADMIN\sqlnet.ora

TNS_ADMIN
C:\ORACEL21C_DATABASE\homes\OraDB21Home3\network\admin