A number of popular websites are either down or running slowly Friday due to an apparent coordinated attack.
Twitter, Etsy, Gitub, Vox, Spotify, Netfli and Reddit all appear to be affected, CNN Money reports.
A Distributed Denial of Service attack (DDoS) is an attack where a website is flooded with so much traffic that normal service is impaired.
According to a statement from Dyn DNS, the outages are due to an attack on east coast servers that started around 7am.
Starting at 11:10 UTC on October 21st-Friday 2016 we began monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure. Some customers may experience increased DNS query latency and delayed zone propagation during this time. Updates will be posted as information becomes available.
It is not yet clear who is responsible for the attack.
The White House press secretary says the Department of Homeland Security is looking into the attacks.