1. Account number or password error: Please check whether the entered account number and password are correct, and pay attention to case sensitivity and special characters.
2. Network connection problem: Please check whether the mobile phone is connected to the Internet and try to switch to different network environments, such as Wi-Fi and mobile data.
3. The APP version is too old: If the Lotte installment app version is too old, there will be login problems and update to the latest version.
4. server maintenance or failure: sometimes the server of lotte installment APP will be maintained or failed, which makes it impossible to log in. At this point, you can try to log in later.