Failed to join any instances

Hey, when i log in, i can go to the various camps in act 1, 2 and 3 and also the camps in all difficulties. However, if i want to go to other areas via waypoints or if they are next to the camp (e.g. lionseye > terraces) i get a message "Error: Failed to join any instances".

I also tried Ctrl-clicking the area entrance and waypoint, but still got the same message.

This happened after i played with my friend and we both logged out and i came on later again. Thanks in advance.