You'll need to be on DNS 8.8.8.8 or 1.1.1.1 to run Scratch Pay.
Go to the Control Panel.
Click Network and Internet > Network and Sharing Center > Change adapter settings.
Select the WiFi connection for which you want to configure. An example is on the left.
If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
Select the Networking tab. Select Properties (highlighted in yellow), then double click on Internet Protocol Version 4 (TCP/IPv4):
Once double clicked, the screen below will pop-up. Select Advanced.
Then, select the DNS tab. If there are any DNS server IP addresses listed there, write them down for future reference, and remove them from this window.
By clicking Edit, replace those addresses with the IP address of 8.8.8.8 or 1.1.1.1, and select "OK" on the small pop-up, and then OK on the DNS window to save.