I've recently had an issue with Digital Ocean servers not being able to ping external websites.
This article has more details: DigitalOcean: https://blog.francium.tech/digitalocean-unable-to-ping-external-websites-9f5d6108de4d
vi /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND — YOUR CHANGES WILL BE OVERWRITTEN nameserver 8.8.8.8 nameserver 8.8.4.4