Thunderbird 78.7.1 cannot access dbus when saving attachments

I suspect that current stable snap for Thunderbird 78.7.1 has some problem with dbus.
When trying to save an attachment (direct save or save as), a line like the following shows up in the kernel log (dmesg), and nothing happens (no file is saved or no dialog shows up)

[87873.665529] audit: type=1107 audit(1613202544.939:1543): pid=1401 uid=103 auid=4294967295 ses=4294967295 subj==unconfined msgindent preformatted text by 4 spaces='apparmor="DENIED" operation="dbus_method_call" bus="system" path="/org/freedesktop/hostname1" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name=":1.757" pid=21770 label="snap.thunderbird.thunderbird" peer_pid=27920 peer_label="unconfined"

As far as I understand there is not interface in this snap to allow this.

    --> snap connections thunderbird
    Interface                 Plug                         Slot                             Notes
    audio-playback            thunderbird:audio-playback   :audio-playback                  -
    avahi-observe             thunderbird:avahi-observe    -                                -
    browser-support           thunderbird:browser-sandbox  :browser-support                 -
    camera                    thunderbird:camera           -                                -
    content[gnome-3-34-1804]  thunderbird:gnome-3-34-1804  gnome-3-34-1804:gnome-3-34-1804  -
    content[gtk-3-themes]     thunderbird:gtk-3-themes     gtk-common-themes:gtk-3-themes   -
    content[icon-themes]      thunderbird:icon-themes      gtk-common-themes:icon-themes    -
    content[sound-themes]     thunderbird:sound-themes     gtk-common-themes:sound-themes   -
    cups-control              thunderbird:cups-control     :cups-control                    -
    desktop                   thunderbird:desktop          :desktop                         -
    desktop-legacy            thunderbird:desktop-legacy   :desktop-legacy                  -
    gpg-keys                  thunderbird:gpg-keys         -                                -
    gsettings                 thunderbird:gsettings        :gsettings                       -
    home                      thunderbird:home             :home                            -
    network                   thunderbird:network          :network                         -
    network-control           thunderbird:network-control  -                                -
    opengl                    thunderbird:opengl           :opengl                          -
    removable-media           thunderbird:removable-media  :removable-media                 manual
    wayland                   thunderbird:wayland          :wayland                         -
    x11                       thunderbird:x11              :x11                             -

Does anybody know a solution or a workaround to this problem?

Snap information are the following

--> snap info thunderbird --verbose
name:    thunderbird
summary: Mozilla Thunderbird email application
  status:  unknown
  message: health has not been set
publisher: Canonical✓
license:   unset
description: |
  Thunderbird is a free and open source email, newsfeed, chat, and calendaring client, that’s easy
  to set up and customize. One of the core principles of Thunderbird is the use and promotion of
  open standards - this focus is a rejection of our world of closed platforms and services that
  can’t communicate with each other. We want our users to have freedom and choice in how they
  - thunderbird
  private:           false
  confinement:       strict
  devmode:           false
  jailmode:          false
  trymode:           false
  enabled:           true
  broken:            false
  ignore-validation: false
base:         core18
snap-id:      k1Ml1O9GzSO2QftV0ZlWSbUfQ78nN460
tracking:     latest/stable
refresh-date: 4 days ago, at 16:32 CET
  latest/stable:    78.7.1 2021-02-08 (110) 69MB -
  latest/candidate: ↑                            
  latest/beta:      86.0b1 2021-02-02 (109) 74MB -
  latest/edge:      78.7.1 2021-02-08 (110) 69MB -
  installed:          78.7.1            (110) 69MB -

Distribution is Ubuntu 18.04.2 LTS.

Thank you in advance for any help on how to solve this.

I solved the above problem by installing xdg-desktop-portals
sudo apt install xdg-desktop-portal xdg-desktop-portal-kde xdg-desktop-portal-gtk

I suppose that people that do not use KDE should avoid to install xdg-desktop-portal-kde.

Some information about xdg-portals and snaps can be found at