I am not sure why but when ever I try to use a nexus cape the item says the following:

The leader of the party is either outside the range of warp or is in an area you have not visited before.

Now I have tried warping from one area over, from within the same zone, and always in places I have already been. I don't know why it is have an issue as I have seen people that are using them to get to places they haven't been. Any help would be nice.