Repository: flutter
Issue: Pub get failed -  Gradle failed with no route to host
Labels: c: regression,tool,t: gradle,found in release: 1.17,P2,team-tool,triaged-tool

I use Android Studio 3.6 on MacosX to develop flutter. My flutter is `Flutter 1.15.17 • channel beta • https://github.com/flutter/flutter.git`.

When I execute `flutter run`, I got these errors:
```
`Launching lib/main.dart on A0001 in debug mode...
Running Gradle task 'assembleDebug'...                                  
                                                                
FAILURE: Build failed with an exception.                                                                           
                                                                                                                   
* What went wrong:                                                                                                 
Execution failed for task ':app:compileDebugKotlin'.                                                               
> Could not resolve all artifacts for configuration ':app:debugCompileClasspath'.                                  
   > Could not download armeabi_v7a_debug.jar (io.flutter:armeabi_v7a_debug:1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852)
      > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/armeabi_v7a_debug/1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852/armeabi_v7a_debug-1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852.jar'.
         > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/armeabi_v7a_debug/1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852/armeabi_v7a_debug-1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852.jar'.
            > Connect to storage.googleapis.com:443 [storage.googleapis.com/216.58.200.48, storage.googleapis.com/2404:6800:4008:801:0:0:0:2010] failed: No route to host (connect failed)
   > Could not download x86_debug.jar (io.flutter:x86_debug:1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852)        
      > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852/x86_debug-1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852.jar'.
         > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_debug/1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852/x86_debug-1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852.jar'.
            > Connect to storage.googleapis.com:443 [storage.googleapis.com/216.58.200.48, storage.googleapis.com/2404:6800:4008:801:0:0:0:2010] failed: No route to host (connect failed)
   > Could not download x86_64_debug.jar (io.flutter:x86_64_debug:1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852)  
      > Could not get resource 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_64_debug/1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852/x86_64_debug-1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852.jar'.
         > Could not GET 'https://storage.googleapis.com/download.flutter.io/io/flutter/x86_64_debug/1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852/x86_64_debug-1.0.0-5aff3119480996ca014ec0f8d26d74db617b5852.jar'.
            > Connect to storage.googleapis.com:443 [storage.googleapis.com/216.58.200.48, storage.googleapis.com/2404:6800:4008:801:0:0:0:2010] failed: No route to host (connect failed)
                                                                                                                   
* Try:                                                                                                             
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
                                                                                                                   
* Get more help at https://help.gradle.org                                                                         
                                                                                                                   
BUILD FAILED in 1m 59s                                                                                             
Running Gradle task 'assembleDebug'...                                                                             
Running Gradle task 'assembleDebug'... Done                       121.6s (!)
Exception: Gradle task assembleDebug failed with exit code 1`
```
It seems that the Gradle could not download the .jar file. But when copy the url into browser, it can be downloaded without any difficulty.

I'm not sure how to solve this problem. Who can give me some advice? Thanks.