Paradoxe

Works with my kde-mint 18.3 but
[22:22:37.807] (II) GREETER: Reading from "/usr/share/xsessions/plasma.desktop"
[22:22:37.807] (EE) GREETER: Socket error: "QLocalSocket::connectToServer : Nom invalide"
[22:22:38.213] (WW) GREETER: file:///usr/share/sddm/themes/nixos-noblur//components/VirtualKeyboard.qml:20:1: module "QtQuick.VirtualKeyboard" is not installed
[22:22:38.233] (WW) GREETER: QFont::setPointSizeF: Point size <= 0 (0.000000), must be greater than 0
[22:22:38.300] (WW) GREETER: file:///usr/share/sddm/themes/nixos-noblur//Main.qml:55:35: Unable to assign [undefined] to QColor
[22:22:38.313] (II) GREETER: Adding view for "DVI-D-1" QRect(0,0 1920x1080) - Oct 15 2019

Hello,
Blank screen with my kde-mint 18.3. - Oct 15 2019

Error with kde-mint 18.3
[21:58:16.096] (II) GREETER: Reading from "/usr/share/xsessions/plasma.desktop"
[21:58:16.097] (EE) GREETER: Socket error: "QLocalSocket::connectToServer : Nom invalide"
[21:58:16.097] (EE) GREETER: Cannot connect to the daemon - is it running?
[21:58:16.387] (WW) GREETER: file:///usr/share/sddm/themes/neontown//Main.qml:129:22: Type Login unavailable
initialItem: Login {
^
[21:58:16.388] (WW) GREETER: file:///usr/share/sddm/themes/neontown//Login.qml:11:1: Type SessionManagementScreen unavailable
SessionManagementScreen {
^
[21:58:16.388] (WW) GREETER: file:///usr/share/sddm/themes/neontown//components/SessionManagementScreen.qml:71:9: Type UserList unavailable
UserList {
^
[21:58:16.388] (WW) GREETER: file:///usr/share/sddm/themes/neontown//components/UserList.qml:21:1: module "QtQuick.Controls" version 2.0 is not installed
import QtQuick.Controls 2.0
^
[21:58:16.388] (II) GREETER: Adding view for "DVI-D-1" QRect(0,0 1920x1080) - Oct 15 2019

Hello,
Blank screen with my kde-mint 18.3.
- Oct 15 2019

Hello,
Ok with my kde-mint 18.3.
- Oct 15 2019

Hello,
Blank screen with my kde-mint 18.3.
Fine whith my kde-Debian 10.1 - Oct 15 2019