Cannot start Flutter web app in Chrome debugger

[Jeff Wilson]

Every time I try to start my Flutter app with a web target, it fails with "unable to connect to port". I can see that Chrome opens briefly and immediately closes. Here's the error:

GAMACL02JW9615:gurps_trait_parser_app jw9615$ flutter run 

Launching lib/main.dart on Chrome in debug mode...

Throwing away cached asset graph due to version mismatch or corrupted asset graph.

Exception: Unable to connect to Chrome debug port: 54686                

 SocketException: OS Error: Connection refused, errno = 61, address = localhost, port = 54688

#0      throwToolExit (package:flutter_tools/src/base/common.dart:28:3) 

#1      ChromeLauncher._connect (package:flutter_tools/src/web/chrome.dart:139:9)

<asynchronous suspension>

#2      ChromeLauncher.launch (package:flutter_tools/src/web/chrome.dart:120:12)

<asynchronous suspension>

#3      WebFs.start (package:flutter_tools/src/build_runner/web_fs.dart:232:48)

<asynchronous suspension>

#4      ResidentWebRunner.run (package:flutter_tools/src/build_runner/resident_web_runner.dart:161:34)

<asynchronous suspension>

#5      RunCommand.runCommand (package:flutter_tools/src/commands/run.dart:460:37)

<asynchronous suspension>

#6      FlutterCommand.verifyThenRunCommand (package:flutter_tools/src/runner/flutter_command.dart:490:18)

#7      _asyncThenWrapperHelper.<anonymous closure> (dart:async-patch/async_patch.dart:71:64)

#8      _rootRunUnary (dart:async/zone.dart:1132:38)

#9      _CustomZone.runUnary (dart:async/zone.dart:1029:19)

#10     _FutureListener.handleValue (dart:async/future_impl.dart:137:18)

#11     Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:678:45)

#12     Future._propagateToListeners (dart:async/future_impl.dart:707:32)

#13     Future._completeWithValue (dart:async/future_impl.dart:522:5)

#14     _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:30:15)

#15     _completeOnAsyncReturn (dart:async-patch/async_patch.dart:288:13)

#16     RunCommand.usageValues (package:flutter_tools/src/commands/run.dart)

#17     _asyncThenWrapperHelper.<anonymous closure> (dart:async-patch/async_patch.dart:71:64)

#18     _rootRunUnary (dart:async/zone.dart:1132:38)

#19     _CustomZone.runUnary (dart:async/zone.dart:1029:19)

#20     _FutureListener.handleValue (dart:async/future_impl.dart:137:18)

#21     Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:678:45)

#22     Future._propagateToListeners (dart:async/future_impl.dart:707:32)

#23     Future._completeWithValue (dart:async/future_impl.dart:522:5)

#24     Future._asyncComplete.<anonymous closure> (dart:async/future_impl.dart:552:7)

#25     _rootRun (dart:async/zone.dart:1124:13)

#26     _CustomZone.run (dart:async/zone.dart:1021:19)

#27     _CustomZone.runGuarded (dart:async/zone.dart:923:7)

#28     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:963:23)

#29     _microtaskLoop (dart:async/schedule_microtask.dart:41:21)

#30     _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)

#31     _runPendingImmediateCallback (dart:isolate-patch/isolate_patch.dart:116:13)

#32     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:173:5)

Building application for the web...                                20.2s

Failed to build application for the web.

And below is the output of flutter doctor -v and flutter config:

GAMACL02JW9615:gurps_trait_parser_app jw9615$ flutter doctor -v

[✓] Flutter (Channel master, v1.10.2-pre.22, on Mac OS X 10.14.6 18G95, locale en-US)

    • Flutter version 1.10.2-pre.22 at /Users/jw9615/Personal/git/flutter

    • Framework revision a7c06e113b (4 hours ago), 2019-09-10 10:29:58 -0700

    • Engine revision 7ea9884ab0

    • Dart version 2.5.0 (build 2.5.0-dev.4.0 be66176534)

 

[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)

    • Android SDK at /Users/jw9615/Library/Android/sdk

    • Android NDK location not configured (optional; useful for native profiling support)

    • Platform android-28, build-tools 28.0.3

    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java

    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)

    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 10.3)

    • Xcode at /Applications/Xcode.app/Contents/Developer

    • Xcode 10.3, Build version 10G8

    • CocoaPods version 1.7.5

[✓] Chrome - develop for the web

    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 3.2)

    • Android Studio at /Applications/Android Studio.app/Contents

    • Flutter plugin version 31.1.1

    • Dart plugin version 181.5656

    • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1136-b06)

[✓] IntelliJ IDEA Community Edition (version 2018.3.2)

    • IntelliJ at /Applications/IntelliJ IDEA CE.app

    • Flutter plugin version 31.3.4

    • Dart plugin version 183.4886.3

[✓] VS Code (version 1.38.0)

    • VS Code at /Applications/Visual Studio Code.app/Contents

    • Flutter extension version 3.4.1

[✓] Connected device (1 available)

    • Chrome • chrome • web-javascript • Google Chrome 76.0.3809.132 

• No issues found!

GAMACL02JW9615:gurps_trait_parser_app jw9615$ flutter config

Configure Flutter settings.

To remove a setting, configure it to an empty string.

The Flutter tool anonymously reports feature usage statistics and basic crash reports to help improve Flutter tools over time. See Google's privacy policy: https://www.google.com/intl/en/policies/privacy/

Usage: flutter config [arguments]

-h, --help                               Print this usage information.

    --[no-]analytics                     Enable or disable reporting anonymously tool usage statistics and crash reports.

    --clear-ios-signing-cert             Clear the saved development certificate choice used to sign apps for iOS device deployment.

    --android-sdk                        The Android SDK directory.

    --android-studio-dir                 The Android Studio install directory.

    --build-dir=<out/>                   The relative path to override a projects build directory

    --[no-]enable-web                    Enable or disable Flutter for web. This setting will take effect on the master and dev channels.

    --[no-]enable-linux-desktop          Enable or disable Flutter for desktop on Linux. This setting will take effect on the master channel.

    --[no-]enable-macos-desktop          Enable or disable Flutter for desktop on macOS. This setting will take effect on the master channel.

    --[no-]enable-windows-desktop        Enable or disable Flutter for desktop on Windows. This setting will take effect on the master channel.

    --[no-]enable-build-plugin-as-aar    Enable or disable Build plugins independently as AARs in app projects. This setting will take effect on the master channel.

    --clear-features                     Remove all configured features and restore them to the default values.

Run "flutter help" to see global options.

Settings:

  enable-web: true

Analytics reporting is currently enabled.

Any help appreciated!

[Hassene KHELIFI]

HI , i have the same problem do have solved it  or not  yet !?

[Alan Maulana]

Connection refused : it means that your current local port has been already used.