Seeing failures when a build server uses rustup to try to acquire Rust 1.14.0. Also reproduced on my machine, trying both 1.14.0-x86_64-unknown-linux-gnu and 1.14.0-x86_64-pc-windows-msvc.
The log shows
info: syncing channel updates for '1.14.0-x86_64-unknown-linux-gnu'
info: latest update on 2016-12-21, rust version 1.14.0 (e8a012324 2016-12-16)
info: downloading component 'rustc'
47.1 MiB / 47.1 MiB (100 %) 32.1 MiB/s ETA: 0 s
info: downloading component 'rust-std'
56.8 MiB / 56.8 MiB (100 %) 29.1 MiB/s ETA: 0 s
info: downloading component 'cargo'
error: component download failed for cargo-x86_64-unknown-linux-gnu
info: caused by: could not download file from 'https://s3.amazonaws.com/rust-lang-ci/cargo-builds/298a0127f703d4c2500bb06d309488b92ef84ae1/cargo-nightly-x86_64-unknown-linux-gnu.tar.gz' to '/home/travis/.rustup/downloads/349a01c2c87f6b5c5cd39ddc6a86a2f6b009a05a48c95a633beea27ac22fed6b.partial'
info: caused by: http request returned an unsuccessful status code: 404
The command "rustup install 1.10.0 1.11.0 1.12.0 1.13.0 1.14.0 1.15.0 1.16.0 1.17.0 1.18.0 1.19.0" exited with 1.
Just taking a quick look at the manifest at https://static.rust-lang.org/dist/channel-rust-1.14.0.toml (compared with 1.13.0 and 1.15.0) I see that all of the cargo URLs are pointing to https://s3.amazonaws.com/rust-lang-ci instead of https://static.rust-lang.org/dist