Been having trouble unlocking the phone - been banging my head on the wall.
Please help before it cracks.

Preliminary: In settings, I have on

• developer mode
• OEM Enabled
• USB Enabled
• Wireless ADB Debugging on

I am using linux computers (linux mint and neon) with adb and fastboot installed via Synaptic Package Manager.

After entering fastboot mode, I type and get

$ fastboot oem unlock
FAILED (remote: 'Flashing Unlock is not allowed
')
fastboot: error: Command failed

I also tried

$ fastboot flashing unlock
FAILED (remote: 'Flashing Unlock is not allowed
')
fastboot: error: Command failed

What am I missing? an utility???

Thank in advanced for your help.

Sheng-Chieh