ExceptionNotification has plugins that talk to external APIs rather then just sends emails, like microsoft teams or slack. You might encounter that no exceptions are delivered, which can be dangerous.
To prevent getting into trouble, simply add
require 'resolv-replace' on top of your to your
require 'resolv-replace' require 'exception_notification/rails' ExceptionNotification.configure do |config| ... end
This calls the Ruby DNS resolver before configuring
ExceptionNotifier so the DNS lookup always works as expected.