caught XIO error

[mjblackhorse]

If you'd like to put out an incentive for fixing this bug, you can do so at https://issuehunt.io/r/LibVNC/x11vnc

Describe the bug Each time I connect with tightvncviewer, it works and I could see the login page of the OS. However, when I enter the correct passwd, the connection is broken and the x11vnc service is stopped.

To Reproduce

1. start x11vnc

   sudo systemctl restart x11vnc.service

   where the file /etc/systemd/system/x11vnc.service is as follows:

   
   [Unit]
   Description=Start x11vnc at startup
   After=multi-user.target
   [Service]
   Type=simple
   ExecStart=/usr/bin/x11vnc -noxdamage -many -display :0 -no6 -rfbport 5900 -rfbauth /etc/x11vnc.pass -auth /var/run/lightdm/root/:0 -o /var/log/x11vnc.log
   [Install]
   WantedBy=multi-user.target

2. Connect with tightvncviewer, and I could see the login page of the OS.
3. Enter the correct password, then the error happens

**Screenshots**
![image](https://github.com/user-attachments/assets/88daa79b-adb7-47d4-93c4-486bfd4749c9)

the log
![image](https://github.com/user-attachments/assets/7c6110f9-aa6e-4be8-a1e1-f7fb2cbc09f0)

**Desktop (please complete the following information):**
 - OS and version: Linux version 5.15.0-117-generic (buildd@lcy02-amd64-102) (gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, GNU ld (GNU Binutils for Ubuntu) 2.38) #127-Ubuntu SMP Fri Jul 5 20:13:28 UTC 2024

 - Xorg version used: 

X.Org X Server 1.21.1.4 X Protocol Version 11, Revision 0 Current Operating System: Linux njucsoj 5.15.0-117-generic #127-Ubuntu SMP Fri Jul 5 20:13:28 UTC 2024 x86_64 Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.15.0-117-generic root=UUID=9cd764cc-e4c0-42ba-a54e-b1719aaabcb6 ro xorg-server 2:21.1.4-2ubuntu1.7~22.04.11 (For technical support please see http://www.ubuntu.com/support) Current version of pixman: 0.40.0 Before reporting problems, check http://wiki.x.org to make sure that you have the latest version.