D-Bus System Message Bus fails to start

SUSE Linux Enterprise Server 15 SP7

After a server reboot, the D-Bus System Message Bus fails to start, causing network service disruptions. The system was not able to activate network connection therefore ssh connectivity was not possible. Logging into the system via console, the following issues can be seen: 

[FAILED] Failed to start D-Bus System Message Bus.
[FAILED] Failed to start wicked managed network interfaces.
[FAILED] Failed to start User Login Managment. 

Checking the dbus.service status, the following error can be seen: 

dbus-daemon[810]: dbus[810]: Failed to start message bus: Error in file /usr/share/dbus-1/system.conf, line 1, column 0: (null)

Looking into above file ( /usr/share/dbus-1/system.conf ), it has the same md5sum from other working system.

1. Comment out the line /opt/IBM/HTTPServer/lib in the file /etc/ld.so.conf.d/httpd-lib.conf.
2. Run the command ldconfig to update the dynamic linker cache.
3. Check the output of ldd to ensure all libraries are loading from the OS side.
4. Reboot the system to verify the fix.

The issue is caused by the system using a non-standard libexpat.so.1 library, which leads to D-Bus failing to read the main configuration file. This can be checked by using ldd command: 

# ldd /usr/bin/dbus-daemon
....
	libexpat.so.1 => /opt/IBM/HTTPServer/lib/libexpat.so.1 (0x00007f1d1ff3e000)
....

Above showing that system is loading libraries from /opt/IBM/HTTPServer/lib instead of the standard OS library /usr/lib64/ .