When sending an email the "From" field does not contain a valid adress

[mb74]

I'm using kmail 5.1.3 (kubuntu 16.04 and kubuntu backports ppa).
In kmail a gmail account is configured and is the default.
When I create new mail only my name is shown in the "From" field: surename name <>
When I reply a mail then "From" field is empty.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
CurrentDesktop: KDE
Date: Sun Jul 24 08:42:27 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2016-07-15 (8 days ago)
InstallationMedia: Kubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
ProcEnviron:
 LANGUAGE=de_AT:de
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_AT.UTF-8
 SHELL=/bin/bash
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)