I’m running a Phoenix app on Fly . I have a GenServer I’m starting as a child in my Application.start/2 function under my MyApp.Supervisor. I had it crash within the GenServer.init/1 function when the app was starting for a deploy. In the logs there was: {exit,terminating,[{application_controller…

Alright, I think you’ve encountered this bug that was fixed in Erlang 27.2.1 Missing error logs when application crashes on OTP-26 · Issue #9163 · erlang/otp · GitHub

Don’t bother with handle_sasl_reports option, it will enable an additional error-level message, but the one you’re interested in is notice-level. This is what I see if I run your case in an empty application in a release locally: {exit,terminating,[{application_controller,call,2,[{file,"application…

There is also this No stack trace in production log - #20 by markmark206 that might be relevant.

Thanks for reproducing this! Here are my versions: elixir 1.17.3-otp-27 erlang 27.1.2 I also thought that maybe the log level was the issue, but I can add Logger.error("Test log") in the GenServer.init/1 and I don’t see that in prod either. I tried it locally with both mix an…