I have a production system, that queues emails in Oban. It sends the emails with Bamboo.Mailer.deliver_now!/4, but it fails with the error (Bamboo.ApiError) :closed a couple of times, until it succeeds, after 2-5 tries.
We use MailGun to send the emails. I contacted MailGun and they can not see anything wrong on their end, I have no idea where to look anymore.

The “fix” right now, is just to try to rerun the job up until 10 times, with a backoff of 15 seconds.
Anyone who has experienced something similar?

Here is the errror:

Attempt 1—now

** (Bamboo.ApiError) :closed
    (bamboo 2.4.0) lib/bamboo/mailer.ex:241: Bamboo.Mailer.deliver_now!/4
    (my_app 0.1.0) lib/my_app/workers/send_email.ex:27: MyApp.Workers.SendEmail.perform/1
    (oban 2.19.4) lib/oban/queue/executor.ex:145: Oban.Queue.Executor.perform/1
    (oban 2.19.4) lib/oban/queue/executor.ex:77: Oban.Queue.Executor.call/1
    (elixir 1.18.3) lib/task/supervised.ex:101: Task.Supervised.invoke_mfa/2
    (elixir 1.18.3) lib/task/supervised.ex:36: Task.Supervised.reply/4