Bug Bleeding Leech Mission (Assassin's Creed: Valhalla)

I need to follow the messenger at the beginning of the mission, I ran up to him and killed him with a hidden blade when he saw me, after that, he stupidly sat down on his knees and nothing can be done with him, the mission does not move forward, I have already gone a lot to roll back, does anyone know how to solve the problem?