Invalid Toolchain - New apps and app updates must be built with the public (GM) versions of Xcode 6 or later, macOS, and iOS SDK. Don't submit apps built with beta software including beta macOS builds.
After you’ve corrected the issues, you can use Xcode or Application Loader to upload a new binary to iTunes Connect.
原因：Xcode9目前还是beta版，无法提交应用。
苹果论坛问题：https://forums.developer.apple.com/thread/17063?sr=stream&ru=18990
解决办法：用正式版Xcode提交
