so i just wanna share how to do this quest and how to trigger it from my own personal experience (since theres sort of a lot of different requirement and talk from guide ive found), i did this twice in a row already with different char today.
go to cobalt forest, there should be an old well on area under Dyveni Wetland, then interact with it, it should say something “rotten”
go to liliana close to blacksmith zaras in klaipeda, talk to her until you get 2 different responses
do seven valley quest, kill as much panto as you can (minimum 20), but just kill as much as you can since they can respawn, and finish the track when its around 2-5s left (it doesnt work if you finish the track first), do it with party its easier.
then go back to an area before you do the track, go north and you can see theres no more barrier
note: torn diary 1-4 probably needed (or maybe not because some player say only have 3 of them, but its good to have), and i believe you have to do main questline until cobalt forest (or maybe not too, since ive finished main quest im not that sure)
sorry for bad english and good luck!