ORA-01017: invalid username/password; logon denied

The error ORA-01017: invalid username/password; logon denied in Oracle Database means that Oracle is not accepting the login credentials you are using.

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🔴 What ORA-01017 Means

👉 The username or password is incorrect, or Oracle cannot authenticate the user.

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🔎 Common Causes & Fixes

1️⃣ Wrong Username or Password

Double-check credentials:

sqlplus username/password

⚠️ Password is case-sensitive in modern Oracle versions.

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🛠 Quick Troubleshooting Checklist

✔ Verify username/password
✔ Check case sensitivity
✔ Check account lock status
✔ Check password expiry
✔ Verify TNS/service name
✔ Check DB link credentials

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📊 Real Production Example

sqlplus emp/test123@PRODDB

Error:

ORA-01017

👉 Root cause:

• Password changed but not updated in application

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✅ Fix Example

ALTER USER emp IDENTIFIED BY new_password;

Update application config with new password.

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⭐ DBA Tip

Run this to verify user:

SELECT username, account_status
FROM dba_users
WHERE username='EMP';

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💡 Important

👉 If login works in one environment but fails in another → check:

• DB link credentials

• Application config

• TNS entries