Hello,

When the connection fails for some reasons, it can be hard to trouble shoot for an inexperienced zbus developer. I'm raising this issue because I passed few days to troubleshoot a system connection failure. I have been able to find the issue by stepping in the code. I found that the system connection is derived from the DBUS_SYSTEM_BUS_ADDRESS environnemental variable and if the variable is not set, it's default to unix:path=/var/run/dbus/system_bus_socket

I propose that the connection error returns the Address as well the current IOError to know to which address zbus tries to connect to ease the troubleshooting.

Thank you