problem with the green proto-drake mission

Well I need help with a problem that I have not solved for a long time, it happens that the first mission of the green proto-drake is to kill a panther and talk to an npc that when killing the panther gives you a mission, when I kill the panther he does not let me speak With the npc that gives him the mission, so I thought it was to go to the next mission if they gave it to me and my surprise was that they didn't give it to me, there was a rogue who couldn't take the mission either, please help me I want the mount .