The link in the docs to the Espressif toolchain setup guide ( http://esp-idf.readthedocs.io/en/v2.1/get-started/index.html#standard-setup-of-toolchain ) seems to be dead - it tries to force you to login. Maybe you could link to this instead: https://docs.espressif.com/projects/esp-idf/en/v2.1.1/get-started/index.html#standard-setup-of-toolchain which is for v2.1.1?
The link in the docs to the Espressif toolchain setup guide ( http://esp-idf.readthedocs.io/en/v2.1/get-started/index.html#standard-setup-of-toolchain ) seems to be dead - it tries to force you to login.
Maybe you could link to this instead: https://docs.espressif.com/projects/esp-idf/en/v2.1.1/get-started/index.html#standard-setup-of-toolchain
which is for v2.1.1?