The Detected unknown package problem occurred while compiling the marlin2.0.x firmware with VSCODE

The Detected unknown package problem occurred while compiling the marlin2.0.x firmware.
My operating system is windows10, there is a problem at compile time, I don't know what to do.
The compilation stopped, and now I don't know what to do to solve the problem.

The output on my build:

> Executing task: C:\Users\Administrator\.platformio\penv\Scripts\platformio.exe run --environment LPC1769 <


Processing LPC1769 (platform: [github.com]; board: nxp_lpc1769; framework: arduino)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

PackageManager: Installing framework-arduino-lpc176x @ >=0.2.2
Error: Detected unknown package 'framework-arduino-lpc176x'
The terminal process terminated with exit code: 1

Terminal will be reused by tasks, press any key to close it.

Edited 1 time(s). Last edit at 04/02/2020 11:26AM by RANDOM588.

vscode is being prevented from accessing the internet. Or your internet is broken...

It needs internet access to download frameworks and libraries

Thank you very much for your advice.
I can compile other boards except nxp_lpc176x.
About the Internet I can install other platforms, plug-ins, frameworks, and libraries normally.
Besides, my location is in China.
Can I install the framework or library by manually updating it?

Edited 1 time(s). Last edit at 04/02/2020 08:49PM by RANDOM588.

Try the following.

Click on platformio home button, find and select the platforms icon, search for "NXP Arduino LPC176x" uninstall and reinstall.

Thanks a lot, I'm now ready to compile the firmware properly