ORA-01017 Invalid Username/Password Error in Oracle – Complete Fix

 ORA-01017: Invalid Username/Password – Complete Solution

The ORA-01017: invalid username/password; logon denied error occurs when Oracle fails to authenticate a connection request. It can also be triggered by case-sensitivity settings, client/server version mismatches, or incorrect environment variables. The ORA-01017 error occurs when Oracle Database rejects login credentials due to incorrect username or password.

Error Message

ORA-01017: invalid username/password; logon denied

Causes

• Wrong username or password
• Case sensitivity issue
• User account locked
• Expired password

Solutions

1. Immediate Fix: Reset the Password 

If you are unsure of the current credentials, the most direct fix is to reset them using administrative privileges.

1. Open your command line and enter: sqlplus / as sysdba.
2. Identify the user and set a new password:

    ALTER USER your_username IDENTIFIED BY "NewPassword123";

3. If the account was locked due to too many failed attempts, unlock it simultaneously:

    ALTER USER your_username ACCOUNT UNLOCK;

2. Handle Case Sensitivity

Starting with Oracle 11g, passwords are case-sensitive by default. If you are using an older client or want to disable this feature: 

• Check current setting: SHOW PARAMETER SEC_CASE_SENSITIVE_LOGON;.
• Disable case sensitivity:

    ALTER SYSTEM SET SEC_CASE_SENSITIVE_LOGON = FALSE;

Note: You may need to reset the user's password again after changing this parameter for it to take effect. 

3. Check Connection Identifiers 

Sometimes the credentials are correct, but you are connecting to the wrong database instance or using an incorrect service name. 

• Verify ORACLE_SID: Ensure your environment variable ORACLE_SID (Linux/Unix) or registry entry (Windows) matches the intended database.
• Check TNSNames: Open your tnsnames.ora file (usually in $ORACLE_HOME/network/admin) to ensure the host, port, and service name are correct.
• Quoted Identifiers: If you created the user with double quotes (e.g., CREATE USER "myUser"...), you must use double quotes every time you log in.

4. Advanced Configuration (Client Mismatch)

If connecting from an older client (e.g., 10g) to a newer server (12c+), authentication may fail due to protocol differences.

Modify sqlnet.ora: Add or update this parameter on the server side to allow older authentication protocols:

    SQLNET.ALLOWED_LOGON_VERSION_SERVER = 8

Restart the Listener: After making changes to sqlnet.ora or tnsnames.ora, restart the Oracle listener service to apply them.

Conclusion

Always verify credentials and ensure the account is active.