Please check the following items in order:

1. Confirm the account format is 6 digits (do not enter email address or phone number)
2. Confirm the password is correct, note that the password is case-sensitive; if you enter it incorrectly multiple times, please reset the password through your personal account
3. Ensure the device can access the internet normally, you can try switching WiFi or mobile data network
4. Check the software log: Invalid account indicates incorrect account or password; Old version indicates the software version is too old, you need to download the latest version from the official website

If the above steps cannot resolve the issue, please contact online customer service and provide a screenshot of the login failure.