unable to login with lxdm

[Claudio Fior]

It happens using lxdm + xfce

cat .xsession-errors

Xsession: X session started for caiofior at gio 5 apr 2018, 14.32.52, CEST
localuser:caiofior being added to access control list
/etc/X11/Xsession: 6: export: Xubuntu.mandatory.path: bad variable name
openConnection: connect: File o directory non esistente
cannot connect to brltty at :0

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: lxdm 0.5.3-1
ProcVersionSignature: Ubuntu 4.4.0-119.143-generic 4.4.114
Uname: Linux 4.4.0-119-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
CurrentDesktop: XFCE
Date: Thu Apr 5 14:34:16 2018
InstallationDate: Installed on 2018-03-02 (34 days ago)
InstallationMedia: Xubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: lxdm
UpgradeStatus: No upgrade log present (probably fresh install)