cups samba authetication dialog closes too early

[Stefan Helmert]

Using network printers with samba authentication on Ubuntu 20.04 the authentication dialog is shown only a very short time and closes unexpectedly. But authentication works with noninteractive authentication using specifying username and password as part of the samba address.

The interactive authentication dialog worked in Ubuntu 18.04 correctly.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: cups 2.3.1-9ubuntu1.1
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.6
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Thu Aug 20 12:57:13 2020
InstallationDate: Installed on 2020-07-07 (43 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
MachineType: LENOVO 20QF00AYGE
Papersize: a4
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-42-generic root=/dev/mapper/vgubuntu-root ro quiet splash vt.handoff=7
SourcePackage: cups
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/13/2020
dmi.bios.vendor: LENOVO
dmi.bios.version: N2HET50W (1.33 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20QF00AYGE
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 31
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN2HET50W(1.33):bd05/13/2020:svnLENOVO:pn20QF00AYGE:pvrThinkPadX1Yoga4th:rvnLENOVO:rn20QF00AYGE:rvrSDK0J40697WIN:cvnLENOVO:ct31:cvrNone:
dmi.product.family: ThinkPad X1 Yoga 4th
dmi.product.name: 20QF00AYGE
dmi.product.sku: LENOVO_MT_20QF_BU_Think_FM_ThinkPad X1 Yoga 4th
dmi.product.version: ThinkPad X1 Yoga 4th
dmi.sys.vendor: LENOVO