... I really feel bad for reporting an error because i like your mod a lot - please don't be discouraged and keep up the impressive work !!!

It is a Krastorio 2 Game with quite some mods, and it is an existing save which previously had your mod active - (the mod has just been updated).

43.146 Error MainLoop.cpp:1202: Exception at tick 2518486: The mod Transport Drones (0.4.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Transport_Drones::on_tick (ID 0)
__Transport_Drones__/script/road_network.lua:308: attempt to index local 'network' (a nil value)
stack traceback:
    __Transport_Drones__/script/road_network.lua:308: in function 'get_network_item_supply'
    __Transport_Drones__/script/depots/buffer_depot.lua:144: in function 'update_contents'
    __Transport_Drones__/script/depots/buffer_depot.lua:257: in function 'update'
    __Transport_Drones__/script/depot_common.lua:271: in function 'update_depots'
    __Transport_Drones__/script/depot_common.lua:279: in function 'handler'
    __core__/lualib/event_handler.lua:44: in function <__core__/lualib/event_handler.lua:42>

feel free to contact me if you need a save or additional information to fix/reproduce the error.