momoko

if i start a new map with the same seed, i could open the vault but if i transfer the old data to new world. the vault will be closed again. but we never opened any vault

so. i copy the world and open it in single player, the chamber still did not recognize me. If i use the same seed level and open a new world in single and it was able to recognize me. However, my friends and I did not open any vault in the chamber before.

How do I find the core?

No. It is a brand new world I started with my friends. And we are first time into the chamber.

is there any prerequisite I need to complete before entering the trial chamber?

i even try it on single player mode. and the vault is still not activate and the mouth is closed

no. not a realms server