Melhor palpite agora é os ataques DDoS em andamento contra a Dyn.
Referências atuais [provavelmente desatualizadas até amanhã]
Update
This DDoS attack may also be impacting Dyn Managed DNS advanced services with possible delays in monitoring. Our Engineers are continuing to work on mitigating this issue.
Posted 24 minutes ago. Oct 21, 2016 - 16:48 UTCInvestigating
As of 15:52 UTC, we have begun monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure. Our Engineers are continuing to work on mitigating this issue.
Posted about 1 hour ago. Oct 21, 2016 - 16:06 UTC
A Major Denial Of Service Attack Brought Down Websites On The US East Coast
After Dyn said it weathered the first attack, it reported another hours later.