Cannot use Serial Monitor

[lobite]

VSCode - Latest (non insider)
Arduino - 0.2.29

When using the Arduino extension with an Adafruit ESP32 Feather (COM3, 80hz, upload speed 921600, serial baud 115200), attempting to open Serial Monitor in VSCode returns the following error.

Failed to open serial port COM3 due to error: + TypeError: Cannot read property 'close' of null

This happens every time and I cannot get Serial Monitor to work within VSCode. Any idea as to why?

(also, I am new here and this is my first issue. Please forgive me if I forgot to include something.)

[hellyzh]

Arduino extension v0.3.0 is released to fix serial port issue which requires vscode 1.43.

[hellyzh]

Duplicate of #980