Story line - I can’t start the silithus quest -

How do reacquire the scroll of teleportation (quest item) to complete the quest line and gain access to the portal todornogal, etc… I’ve looked online and there isn’t clear info on how it’s done. One option is to (shift J) quest tracker and select the war within tab, to reacquire it, but I haven’t found an option to interact with for this. Has anyone found a way around this? It’s not in my bank or my bags. Thanks