For the past several days the server has been unable to resolve external DNS addresses. I’m not sure how long exactly, but based on the notification email retry queue I’d say 3 to 4 days.
This had three major impacts:
- Notification mails have not been sent
- Login from a github sign in didn’t work
- A site upgrade was botched leading to a few hours of down time
I do not know what caused DNS resolution to fail. After a bunch of fix attempts, I managed to get it working with a 3rd party DNS provider. I’m sure that will come back to haunt me later.
Docker and Discourse are now updated to the latest version.