Modern Tecno devices, including the BE6j, come with factory reset protection (FRP) and secure boot protocols enabled. When you try to flash a Stock ROM, the tool verifies the device's authenticity. If the default connection fails, you need a specific DA file to authorize the flashing process.
Below is the link to download the necessary files. Ensure you have proper antivirus disabled temporarily during extraction, as some security software might falsely flag flashing tools. Tecno Be6j Da File
You can download the DA file for Tecno Be6j from the following sources: Modern Tecno devices, including the BE6j, come with