Flutter Gradle build failed with an exception

In my company behind our proxy i can't start a flutter project. I don't get gradle running.

I set this config into gradle.properties:

systemProp.http.proxyHost=http://my.company.com
systemProp.http.proxyPort=8080
systemProp.http.nonProxyHosts=127.0.0.1|localhost
systemProp.https.proxyHost=http://my.company.com
systemProp.https.proxyPort=8080
systemProp.https.nonProxyHosts=127.0.0.1|localhost

SSL encrypted traffic will be decrypted. We have self signed certificates on our proxy server. I don't find any way to tell gradle the path to my certs.pem file.

The stacktrace

Launching lib\main.dart on Android SDK built for x86 in debug mode...
Initializing gradle...
Resolving dependencies...
* Error running Gradle:
Exit code 1 from: C:\Users\i01002704\Documents\Projects\Android\time_tracker\android\gradlew.bat app:properties:

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'android'.
> Could not resolve all files for configuration ':classpath'.
   > Could not resolve com.android.tools.build:gradle:3.1.4.
     Required by:
         project :
      > Could not resolve com.android.tools.build:gradle:3.1.4.
         > Could not get resource 'https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/3.1.4/gradle-3.1.4.pom'.
            > Could not GET 'https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/3.1.4/gradle-3.1.4.pom'.
               > http://my.company.com
      > Could not resolve com.android.tools.build:gradle:3.1.4.
         > Could not get resource 'https://jcenter.bintray.com/com/android/tools/build/gradle/3.1.4/gradle-3.1.4.pom'.
            > Could not GET 'https://jcenter.bintray.com/com/android/tools/build/gradle/3.1.4/gradle-3.1.4.pom'.
               > http://my.company.com
   > Could not resolve org.jetbrains.kotlin:kotlin-gradle-plugin:1.2.61.
     Required by:
         project :
      > Could not resolve org.jetbrains.kotlin:kotlin-gradle-plugin:1.2.61.
         > Could not get resource 'https://dl.google.com/dl/android/maven2/org/jetbrains/kotlin/kotlin-gradle-plugin/1.2.61/kotlin-gradle-plugin-1.2.61.pom'.
            > Could not GET 'https://dl.google.com/dl/android/maven2/org/jetbrains/kotlin/kotlin-gradle-plugin/1.2.61/kotlin-gradle-plugin-1.2.61.pom'.
               > http://my.company.com
      > Could not resolve org.jetbrains.kotlin:kotlin-gradle-plugin:1.2.61.
         > Could not get resource 'https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-gradle-plugin/1.2.61/kotlin-gradle-plugin-1.2.61.pom'.
            > Could not GET 'https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-gradle-plugin/1.2.61/kotlin-gradle-plugin-1.2.61.pom'.
               > http://my.company.com

* 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 1s

Finished with error: Please review your Gradle project setup in the android/ folder.