Error downloading http://arduino.esp8266.com/stable/package_esp8266com_index.json

[juztinfied]

Does anyone have any issues with the board manager for WE MOS D1 R2 ESP8266? The board now does not even appear on my IDE list of arduino boards

[devyte]

Works for me.
Closing as can't reproduce.

[zcattacz]

Can't Open it Now.

[devyte]

Still works for me.

[zcattacz]

HTTP error code 416. Arduino IDE's download manager is to blame.
remove tmp file before retry.
arduino/Arduino#6628

[MuhammadShoaibJahangir]

The issue with the boards disappearing is definitely a bug with the Arduino IDE. You can get the boards back by:
https://github.com/esp8266/Arduino/releases/download/2.3.0/package_esp8266com_index.json

to File > Preferences > Additional Boards Manager URLs
Tools > Board > Boards Manager
Wait for downloads to complete.
Click "Close" (don't install the ESP8266 boards, you already have them installed)
The ESP8266 boards will now appear in your Tools > Board menu again.