Astrill Setup Manual:How to configure DNS on network adapter on Windows 10
Open Control Panel, click on Network and Internet then click on Network and Sharing Center.
On the left pane, click on Change adapter settings.
Right-click on your active internet connection (this may be "Ethernet", "Wireless Network Connection" or "Local Area Connection" depending on how your computer is set up) and select Properties.
In the Networking tab, click once on Internet Protocol Version 4 (TCP/IPv4) to highlight it, and then click Properties.
Select Use the following DNS server addresses and then enter the following:
Preferred DNS server: 18.104.22.168
Alternate DNS server: 22.214.171.124
Then click OK.
To confirm if the DNS server addresses is already set, right-click on your active internet connection again and select Status.
Click on Details....
Under Network Connection Details, you will see 126.96.36.199 and 188.8.131.52 as DNS servers for IPv4. This is a confirmation that DNS has been set.
You can click on Close button now.