Oracle has a variety of connection errors, some with an unclear relationship to the actual issue.
- The type initializer for 'OracleInternal.Network.AddressResolution' threw an exception.
- Value cannot be null.
- Parameter name: path1
This issue is that the file "sqlnet.ora" is missing the keyword "NAMES.DIRECTORY_PATH". If no previous value existed then a reasonable starting value is:
Multiple options are possible. Beware of referring to non-existing services.
NAMES.DIRECTORY_PATH=(tnsnames, ldap, ezconnect)