WiFi hotspot with WPA/WPA2 Personal security doesn't work with Windows 10 client

[Horst Schirmeier]

When I create a shared WiFi ("hotspot") in the "Connections - System Settings Module" with enabled WPA/WPA2 security, I cannot get Windows 10 clients to connect. Android 10 connects to this shared WiFi without problems. Using the "Hotspot" button behind the system-tray network icon works with Windows 10 clients (but creates an open/unencrypted WiFi).

STEPS TO REPRODUCE
1. Go to System Settings -> Network / Connections
2. Add a new network ("+"), Connection Type: "Wi-Fi (shared)"
3. Pick an appropriate connection and SSID name (e.g. "xyz", "xyz"). Mode: "Access Point".
4. "Security" tab: Security "WPA/WPA2 Personal", pick a password. Save.
5. "Connect" to this newly created network, enabling the Wi-Fi access point.
6. Try to connect to this AP with a Windows 10 client.

OBSERVED RESULT
1. When clicking on the "xyz" Wi-Fi, Windows 10 (EDU, Version 1909, Build 18363.418) asks for an eight-digit PIN instead of a password, unlike for other WiFis. It is, however, also possible to click a link below and enter the previously set AP password.
2. Windows 10's Wi-Fi dialog reports that it cannot connect to this network ("Keine Verbindung mit diesem Netzwerk möglich"). This is reproducible with different Windows 10 machines.
3. A Sony Xperia XZ2 Compact with Android 10 connects to the "xyz" AP without problems.

EXPECTED RESULT
Windows 10 should connect to the AP without problems, just like Android 10 does, or just as Windows 10 does to the unencrypted AP.

SOFTWARE/OS VERSIONS
Windows: Windows 10 Education, 1909, Build 18363.418
macOS:
Linux: Kubuntu 20.04
KDE Plasma Version: 5.18.4 (4:5.18.4.1-0ubuntu1)
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.5

I haven't tried this with earlier Kubuntu versions, but got one report that this bug cannot be reproduced with Ubuntu 19.10.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: network-manager 1.22.10-1ubuntu1
ProcVersionSignature: Ubuntu 5.4.0-21.25-generic 5.4.27
Uname: Linux 5.4.0-21-generic x86_64
ApportVersion: 2.20.11-0ubuntu25
Architecture: amd64
CurrentDesktop: KDE
Date: Wed Apr 8 22:35:27 2020
IfupdownConfig:
 # interfaces(5) file used by ifup(8) and ifdown(8)
 auto lo
 iface lo inet loopback
InstallationDate: Installed on 2016-11-26 (1229 days ago)
InstallationMedia: Kubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.1)
IpRoute:
 default via 192.168.178.1 dev wlp3s0 proto dhcp metric 600
 169.254.0.0/16 dev wlp3s0 scope link metric 1000
 192.168.178.0/24 dev wlp3s0 proto kernel scope link src 192.168.178.69 metric 600
SourcePackage: network-manager
UpgradeStatus: Upgraded to focal on 2020-03-06 (33 days ago)
mtime.conffile..etc.NetworkManager.NetworkManager.conf: 2017-11-20T11:33:29
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.22.10 connected started full enabled enabled enabled enabled disabled

[Horst Schirmeier (horst)]

KDE bug report: https://bugs.kde.org/show_bug.cgi?id=419745

[Sebastien Bacher (seb128)]

Thank you for your bug report, could you also report it upstream on https://gitlab.freedesktop.org/NetworkManager/NetworkManager ?

[Horst Schirmeier (horst)]

In my KDE bug report (https://bugs.kde.org/show_bug.cgi?id=419745) I filed against systemsettings/kcm_networkmanagement; I'm actually not sure whether network-manager was the right package to file against, are you?

[Sebastien Bacher (seb128)]

Could you trigger the issue and then add your 'journalctl -b 0' log?