When logging in I too got a black screen. It was because windows firewall is blocking access.

Go to control panel then windows firewall.

make sure fallout 4 has access.

in windows 10 you need to click the edit button with the admin icon on top. other versions would be similar you may need to navigate to your games directory to add the game if it is not listed.

(win 10 location): this pc/c:/programfilesx86/steam/steamapps/common/fallout4

---(the windows 7 version is almost identical except the "this PC" part.

hope this helps!

now if someone could explain why my phone app is useless...my PC is on a wired connection yet the app looks for my pc and phone to be on the same WiFi. im not going to use wifi on my pc when its 8 inches from the router!