The situation
On a Xerox call, the fault isn't always the printer. When it turns out to be the network, technically out of my scope, I don't like leaving a customer stuck.
What I did
A bank couldn't send print jobs to one of their machines. I traced it back through the patch panel to the port and saw it right there: the panel's ethernet cable was unplugged. I flagged it to their IT, and with their OK I plugged it back in and got a link light. A reboot of the printer and it was back on the network. The cause turned out to be their ISP, who had been in doing work and left that cable out by mistake.
What I take from it
It isn't my system to change, so I diagnose, document, and hand the fix to their IT to approve, often working it through with them directly. It respects the boundary, and it's the kind of work that bridges this field role to the network and systems role I'm aiming for.