I had left that quest aside, creat another char, and in the same quest when I got to that part the same thing happened, so it occurred to me that I did not go to Ancient City Arcan through the cave, but through global gk, and that was the problem .
The npc does not recognize that the char continues the quest, so it offers the dialogue of the other quest that has nothing to do.
So I went back to Angels Waterfall and went to Ancient City through the cave, so I managed to get on the quest.