Ubuntu 22.04 基于Dummy虚拟显卡的远程桌面突然无法连接问题求助

各位好，我遇到了一个非常头疼的问题，想请社区的大佬们帮忙排查下：

我用Windows 11电脑远程连接一台无物理显示器的Ubuntu 22.04桌面，之前好几个月都运行得很正常。因为这台Ubuntu没接实体显示器，我专门安装了xserver-xorg-video-dummy包，并且配置了/etc/X11/xorg.conf，具体配置内容如下：

Section "Monitor"
  Identifier "Monitor0"
  HorizSync 28.0-80.0
  VertRefresh 48.0-75.0
  # 1920x1080 @ 60.00 Hz (GTF) hsync: 67.08 kHz; pclk: 172.80 MHz
  Modeline "1920x1080_60.00" 172.80 1920 2040 2248 2576 1080 1081 1084 1118 -HSync +Vsync
EndSection
Section "Device"
  Identifier "Card0"
  Driver "dummy"
  VideoRam 256000
EndSection
Section "Screen"
  DefaultDepth 24
  Identifier "Screen0"
  Device "Card0"
  Monitor "Monitor0"
  SubSection "Display"
    Depth 24
    Modes "1920x1080_60.00"
  EndSubSection
EndSection

结果最近这个配置突然失效了：现在发起远程连接时，输入密码点击OK后，远程桌面窗口只会闪一下就立刻消失。查看/var/log/syslog，发现了以下关键报错信息：

Mar 18 11:32:29 testcomputer gnome-remote-desktop-daemon[2736]: [11:32:29:978] [2736:3633] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_CONTINUE_NEEDED [0x00090312]
Mar 18 11:32:29 testcomputer gnome-remote-desktop-daemon[2736]: [11:32:29:981] [2736:3633] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_COMPLETE_NEEDED [0x00090313]
Mar 18 11:32:30 testcomputer gnome-remote-de[2736]: Failed to start remote desktop session: GDBus.Error:org.freedesktop.DBus.Error.AccessDenied: Session creation inhibited
Mar 18 11:32:30 testcomputer gnome-remote-desktop-daemon[2736]: [11:32:29:008] [2736:2736] [ERROR][com.freerdp.core] - rdp_set_error_info:freerdp_set_last_error_ex ERRINFO_RPC_INITIATED_DISCONNECT [0x00010001]

为了对比，我贴出之前连接正常时的syslog日志内容：

Mar 18 11:01:52 testcomputer gnome-remote-desktop-daemon[2736]: [11:01:52:363] [2736:3435] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_CONTINUE_NEEDED [0x00090312]
Mar 18 11:01:52 testcomputer gnome-remote-desktop-daemon[2736]: [11:01:52:365] [2736:3435] [WARN][com.winpr.negotiate] - AcceptSecurityContext status SEC_I_COMPLETE_NEEDED [0x00090313]
Mar 18 11:01:52 testcomputer gnome-remote-de[2736]: [RDP.RDPGFX] CapsAdvertise: Accepting capability set with version RDPGFX_CAPVERSION_106, Client cap flags: H264 (AVC444): true, H264 (AVC420): true
Mar 18 11:01:52 testcomputer gnome-remote-de[2736]: [RDP.CLIPRDR] Client capabilities: long format names, stream file clip, file clip no file paths, can lock clip data, huge file support
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 34 with keysym 34 (keycode d).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 35 with keysym 35 (keycode e).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 31 with keysym 31 (keycode a).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 32 with keysym 32 (keycode b).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 33 with keysym 33 (keycode c).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 36 with keysym 36 (keycode f).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 38 with keysym 38 (keycode 11).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 37 with keysym 37 (keycode 10).
Mar 18 11:01:53 testcomputer gnome-shell[2782]: Window manager warning: Overwriting existing binding of keysym 39 with keysym 39 (keycode 12).

现在我最核心的疑问就是这条错误提示：
Failed to start remote desktop session: GDBus.Error:org.freedesktop.DBus.Error.AccessDenied: Session creation inhibited

另外还有一个很奇怪的现象可以提供线索：如果给这台Ubuntu临时接上物理显示器，远程桌面就能立刻恢复正常；而且拔掉显示器后，用dummy虚拟显卡的远程连接还能正常运行几分钟，之后就又突然失效了。

有没有大佬遇到过类似的问题？或者能帮我分析下这个错误的原因，以及对应的解决办法？非常感谢！

备注：内容来源于stack exchange，提问作者Alberto Amori