Impossible task. Floating mark on the map. [Help!] (Fallout 4)

Faced a problem in the game. The quest marker floats across the map. How to cure or what to do? I am attaching a video. I can’t get through, because without this mission I will not be able to complete the game completely or this task does not affect the plot in any way? Or can I score on this mission and I will calmly reach the end of the plot and find out everything?
http://www.playground.ru/redirect/