Proxy authentication error 407 even if 'check proxy' works

awt.toolkit sun.awt.windows.WToolkit executable-war D:\Jenkins\jenkins.war file.encoding Cp1252 file.encoding.pkg sun.io file.separator \ hudson.lifecycle hudson.lifecycle.WindowsServiceLifecycle java.awt.graphicsenv sun.awt.Win32GraphicsEnvironment java.awt.headless true java.awt.printerjob sun.awt.windows.WPrinterJob java.class.path D:\Jenkins\jenkins.war java.class.version 52.0 java.endorsed.dirs D:\Jenkins\jre\lib\endorsed java.ext.dirs D:\Jenkins\jre\lib\ext;C:\Windows\Sun\Java\lib\ext java.home D:\Jenkins\jre java.library.path D:\Jenkins\jre\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;. java.runtime.name Java(TM) SE Runtime Environment java.runtime.version 1.8.0_144-b01 java.specification.name Java Platform API Specification java.specification.vendor Oracle Corporation java.specification.version 1.8 java.vendor Oracle Corporation java.vendor.url http://java.oracle.com/ java.vendor.url.bug http://bugreport.sun.com/bugreport/ java.version 1.8.0_144 java.vm.info mixed mode java.vm.name Java HotSpot(TM) Client VM java.vm.specification.name Java Virtual Machine Specification java.vm.specification.vendor Oracle Corporation java.vm.specification.version 1.8 java.vm.vendor Oracle Corporation java.vm.version 25.144-b01 jna.loaded true line.separator os.arch x86 os.name Windows Server 2016 os.version 10.0 path.separator ; sun.arch.data.model 32 sun.boot.class.path D:\Jenkins\jre\lib\resources.jar;D:\Jenkins\jre\lib\rt.jar;D:\Jenkins\jre\lib\sunrsasign.jar;D:\Jenkins\jre\lib\jsse.jar;D:\Jenkins\jre\lib\jce.jar;D:\Jenkins\jre\lib\charsets.jar;D:\Jenkins\jre\lib\jfr.jar;D:\Jenkins\jre\classes sun.boot.library.path D:\Jenkins\jre\bin sun.cpu.endian little sun.cpu.isalist pentium_pro+mmx pentium_pro pentium+mmx pentium i486 i386 i86 sun.desktop windows sun.io.unicode.encoding UnicodeLittle sun.java.command D:\Jenkins\jenkins.war --httpPort=8080 --webroot=D:\Jenkins\war sun.java.launcher SUN_STANDARD sun.jnu.encoding Cp1252 sun.management.compiler HotSpot Client Compiler sun.os.patch.level user.country US user.country.format AT user.dir D:\Jenkins user.language en user.language.format de user.script user.timezone Europe/Berlin user.variant Umgebungsvariablen Name ↓ Wert ALLUSERSPROFILE C:\ProgramData BASE D:\Jenkins CommonProgramFiles C:\Program Files (x86)\Common Files CommonProgramFiles(x86) C:\Program Files (x86)\Common Files CommonProgramW6432 C:\Program Files\Common Files ComSpec C:\Windows\system32\cmd.exe JENKINS_HOME D:\Jenkins NUMBER_OF_PROCESSORS 2 OS Windows_NT Path C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\ PATHEXT .COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC PROCESSOR_ARCHITECTURE x86 PROCESSOR_ARCHITEW6432 AMD64 PROCESSOR_IDENTIFIER Intel64 Family 6 Model 26 Stepping 4, GenuineIntel PROCESSOR_LEVEL 6 PROCESSOR_REVISION 1a04 ProgramData C:\ProgramData ProgramFiles C:\Program Files (x86) ProgramFiles(x86) C:\Program Files (x86) ProgramW6432 C:\Program Files PSModulePath %ProgramFiles%\WindowsPowerShell\Modules;C:\Windows\system32\WindowsPowerShell\v1.0\Modules PUBLIC C:\Users\Public RANDFILE C:\ProgramData\.rnd SERVICE_ID Jenkins SystemDrive C: SystemRoot C:\Windows UATDATA C:\Windows\CCM\UATData\D9F8C395-CAB8-491d-B8AC-179A1FE1BE77 windir C:\Windows WINSW_EXECUTABLE D:\Jenkins\jenkins.exe WINSW_SERVICE_ID Jenkins Plugins: Keine Plugins installiert.