The mod Construction Drones caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Construction_Drones::on_script_path_request_finished (ID 112)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
Construction_Drones/script/construction_drone.lua:1330: in function 'clear_target'
Construction_Drones/script/construction_drone.lua:2500: in function 'handler'
core/lualib/event_handler.lua:44: in function <core/lualib/event_handler.lua:42>
stack traceback:
[C]: in function 'index'
__Construction_Drones/script/construction_drone.lua:1330: in function 'clear_target'
Construction_Drones/script/construction_drone.lua:2500: in function 'handler'
core/lualib/event_handler.lua:44: in function <core/lualib/event_handler.lua:42>