The issue has been identified and a fix is being implemented.
Posted 13 days ago. Feb 06, 2019 - 17:12 UTC
On February 6th, 2019, between 16:33 UTC and 16:44 UTC, Dyn engineers performed emergency maintenance on our Managed DNS API. Users interacting with the API may have experienced failed or delayed transactions. No impact to Dyn Managed DNS Nameservers or other peripheral infrastructure is expected.
Customers with any questions are encouraged to reach out to our Product Support Team.