ping displays "Name or service not known"

I am running Arch Linux on a Raspberry Pi. Suddenly: 1. I am unable to ping to a website. 2. I am unable to access a website from the browser. I have two more computers (all running Arch Linux) connected to the Internet, where I can ping and use the Internet. Also, /etc/resolv.conf is identical on the other computers:

nameserver 10.230.252.252
nameserver 203.147.88.2
nameserver 8.8.8.8
search domain.name

I can use VNC. I can also ping to 8.8.8.8. When trying to access DuckDuckGo on Chromium I get:

This site can’t be reached
duckduckgo.com’s server IP address could not be found.
DNS_PROBE_FINISHED_NXDOMAIN

I have an active Internet connection. What's wrong?