The mod Items Network [BETA] (1.9.6) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event items-network::on_gui_click (ID 1)
items-network/scripts/terminal_gui.lua:392: attempt to index field '?' (a nil value)
stack traceback:
items-network/scripts/terminal_gui.lua:392: in function 'handler'
items-network/scripts/lib/events.lua:63: in function '?'
items-network/scripts/lib/events.lua:30: in function 'on_event'
items-network/scripts/lib/events.lua:15: in function <items-network/scripts/lib/events.lua:15>

Thanks for the report! This turned out to be on the items-network side, not in factory_solver. I'll pass it along to the items-network author for you, so you don't have to chase it down twice. No action needed from you — sorry for the trouble.

Oh I didn't notice. I just figured it was this mod based on the gui I clicked on... lol Thanks