I have two portable "installations" of the Arduino-IDE on my laptop
Arduino 1.8.13 and 1.8.16
the 1.8.16 shows an error-message
error downloading https://downloads.arduino.cc/library_index.json
thank you J-M-L the correct URL is
while the 1.8.13-version can download it.
I'm not aware of having changed something in my 1.8.16-version.
what can cause this error ? What do I have to check to fix it?
best regards Stefan