Libary fails to load in arduino ide

Hi,

I am using Nodemcu with arduinio ide. Usually I select Generic ESP8266 libarary in library manager. Last few weeks I am not able to load that library. In display I am getting an error while loading the library. Kindly suggest.

Libraray in Preferences:

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

Reference: screen shot attached

Regards
karthik s

Can you open the URL http://arduino.esp8266.com/stable/package_esp8266com_index.json in your browser?