Benusta:
The instance zone is inaccessible at the time.
Only your party leader can ask me for the first-time visit to the instance zone. There is no other way to enter.
Keep in mind that the party cannot move to an instance zone if there is a character in the party, which does not meet level requirements. Also teleportation will be impossible if any of the party members stand too far from me.
Also you cannot enter an instance zone if other party is already in. Please, check the requirements once more.