At some point a few weeks ago email started failing. I haven’t had time to address it until now, and I’m at a bit of a loss.
There was a similar problem here: Error: "There are 965 email jobs that failed. Check your app.yml and ensure that the mail server settings are correct." that was solved by rebooting the server.
I tried rebooting the droplet, but that doesn’t seem to have helped. What else can I try?
There is a chance there is something wrong at your email service provider’s end. What service are you using for sending emails?
I suspect you might be right. I set up email through name.com; that’s who is hosting the DNS. I don’t see anything strange there, but I’m not sure what to look for.
Check the plan your on for your mail server. A client ran into this issue when they were exceeding the plan they were on
That doesn’t seem to be it, but good suggestion!
I don’t think name.com offers an email server for bulk sending. But this issue is most certainly related to your mail server either refusing the mails or your host server having wrong email credentials (which is unlikely if the same credentials worked before.)
Name.com offers email through cPanel.
I think I must have screwed it up when I made some configuration changes at the end of September which I didn’t precisely log 
. Currently can’t telnet to the server.
I rebuilt with ./discourse-setup which didn’t help, and I’m just not seeing anything odd on the cPanel or Name.com side. I wonder if I screwed up the DKIM/SPF incantation. I’m going to look there next.
This shouldn’t be causing email jobs to fail in discourse.