Problems with swadows and lightning

After 2 mouth of working shadows in one moment became like on the picture, what i did wrong?
Please help, spent half a day to solve this!

305463-без-имени-2.png

You may find answer for your problem here: Build problem

Как Firewall и VPN может повлиять на Building Lightning в UE4? Я на всякий случай проверил - не помогло((