How can run skype in background?

The latest way to install skype is with snap.

sudo snap install skype

Reboot,it can be started automatically and run in background daemon way.We can enable or disable its automatical startup in setting menu.It runs when automatical startup disabled:

sudo snap run skype

But the command can’t be run in background as a normal daemon.

snap run skype  &
snap run skype  2>&1

All of them have same output: + [ -f /home/debian/snap/skype/common/.config/skypeforlinux/settings.json ] + export SKYPE_LOGS=/home/debian/snap/skype/293/logs + [ ! -d /home/debian/snap/skype/293/logs ] + exec /snap/skype/293/usr/share/skypeforlinux/skypeforlinux

(skypeforlinux:7018): dbind-WARNING **: 08:37:42.359: Couldn't connect to accessibility bus: Failed to connect to socket /tmp/dbus-Sn7hKIkXXv: No such file or directory
[7018:0828/083745.138649:ERROR:browser_main_loop.cc(271)] Gdk: gdk_window_thaw_toplevel_updates: assertion 'window->update_and_descendants_freeze_count > 0' failed
[7018:0828/083748.837416:ERROR:object_proxy.cc(623)] Failed to call method: org.freedesktop.ScreenSaver.GetActive: object_path= /org/freedesktop/ScreenSaver: org.freedesktop.DBus.Error.UnknownMethod: Unknown method GetActive or interface org.freedesktop.ScreenSaver.
Error occurred in handler for 'keychain:get-password': Error: No stored credentials fetched from keytar.
    at /snap/skype/293/usr/share/skypeforlinux/resources/app.asar/main.js:2:508550
    at async node:electron/js2c/browser_init:193:551
Error occurred in handler for 'keychain:get-password': Error: No stored credentials fetched from keytar.
    at /snap/skype/293/usr/share/skypeforlinux/resources/app.asar/main.js:2:508550
    at async node:electron/js2c/browser_init:193:551
Error occurred in handler for 'keychain:get-password': Error: No stored credentials fetched from keytar.
    at /snap/skype/293/usr/share/skypeforlinux/resources/app.asar/main.js:2:508550
    at async node:electron/js2c/browser_init:193:551
Error occurred in handler for 'keychain:get-password': Error: No stored credentials fetched from keytar.
    at /snap/skype/293/usr/share/skypeforlinux/resources/app.asar/main.js:2:508550
    at async node:electron/js2c/browser_init:193:551

Both of them can’t make it run in background,how can run it in background then?