Horn of Vastari

My character is a level 30 ranger. Acquired the horn and went to the front of the caravan and nothing opens to allows sounding the horn. Have seen how it works on you-tube so I'm aware of the actions needed.

Reloading doesn't help. Neither does recycling thru the locations to get to the
proper place to sound the horn.

And all of my waypoints show closed on the desert map unless I travel to another location, get off, find a waypoint: then can access other way point.

Ashlander#7779