Bug#1036403: Unable to accept server certificate in Kalendar

Package: kalendar
Version: 22.12.3-1
User: Mikolaj
Severity: important

When I try to add remote (from my Nextcloud instance) calendar in KDE's Kalendar app, I am not able to accept the server's (self signed) certificate - the window completely freezes (window's title: Server-Authentifizierung -- akonadi_davgroupware_resource_4), I cannot click any button, even the buttons don't change their state (appearance) when I hover or click them. When I try to close the window by clicking the close button, it doesn't work. I also noticed another probably related bug - when I try to add remote directory (SFTP connection) in Dolphin (when you open Dolphin, you have "Network" category on left), I wasn't able to accept server's ssh certificate, because the window also freezes. After a few tries (I don't know how) I accepted it, but also got the following message from KDE Plasma Desktop:

KNetAttach
Prüfung (Fehlgeschlagen)
Die Anwendung wurde unerwartet beendet.

I think that the problem may also be related with apps like Akonadi and KNetAttach (and Wayland?) and the bug may also affect other KDE applications, that allow to connect with remote servers.

I am using Debian 12 Bookworm (testing), KDE Plasma Desktop (version: 4:5.27.2-2, but the bug occured also on version 4:5.27.2-1) and Wayland.
plasma-framework version: 5.103.0-1
Qt version: 5.18.8
Kernel version: 6.1.27-1 amd64

I am using swiss keyboard layout and system language is Schweizer Hochdeutsch (swiss german).