WDS UEFI Uattended Domainjoin Problems

Hello Everyone,

We try to deploy Windows 10 x64 Enterprise with UEFI machines.

The WDS Server Plattform is 2012 R2 x64.

Im Playing around with Domainjoin for one Week now and cannot find an answer.

Panther Setuperr.log gives me:
2017-01-18 14:14:47, Error                        [DJOIN.EXE] Unattended Join: NetJoinDomain failed error code is [5]
2017-01-18 14:14:48, Error                        [DJOIN.EXE] Unattended Join: Unable to join; gdwError = 0x5

Unattended File is with flags

  <settings pass="specialize">
        <component name="Microsoft-Windows-UnattendedJoin" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
            <Identification>
                <Credentials>
                    <Domain>xxx</Domain>
                    <Username>mdtinstall</Username>
                    <Password>xxx</Password>
                </Credentials>
                <JoinDomain>xxx</JoinDomain>
                <DebugJoin>true</DebugJoin>
                <TimeoutPeriodInMinutes>1</TimeoutPeriodInMinutes>
            </Identification>
        </component>
        <component name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
            <TimeZone>W. Europe Standard Time</TimeZone>
            <ProductKey>NPPR9-FWDCX-D2C8J-H872K-2YT43</ProductKey>
            <ComputerName>%MACHINENAME%</ComputerName>
            <RegisteredOrganization>xxx</RegisteredOrganization>
            <RegisteredOwner>IT Department</RegisteredOwner>
        </component>
    </settings>

any suggestions?