How to handle Postmark delivery errors (Postmark::InvalidMessageError) in Rails mailers

TL;DR

For "Postmark::InvalidMessageError": on Rails 4.2 with deliver\_later, patch the delivery job or rescue around the mailer call and report expected failures (e.g.

Postmark::InvalidMessageError

Steps

1. On Rails 5+, use ActionMailer's exception handling: ActionMailer::Base.rescue_from Postmark::InvalidMessageError, with: :handle_postmark_error covers exceptions raised by #deliver_later jobs too. On Rails 4.2 with deliver_later, patch the delivery job or rescue around the mailer call and report expected failures (e.g. ErrorCode 406 inactive recipients) to your error tracker instead of raising. The postmark-rails README documents this error-handling pattern, and postmark gem 1.11.0+ ships more granular exception classes (e.g. Postmark::InactiveRecipientError).

When to use

You are seeing this: On Rails 4.2.4 with postmark-rails and DelayedJob-backed ActiveJob, delivery errors such as Postmark::InvalidMessageError (e.g. sending to [redacted address]) need to be handled both for deliver\now and deliver\later, without spamming the error logs for... Use this skill when you run into "How to handle Postmark delivery errors (Postmark::InvalidMessageError) in Rails mailers".

When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

Versions mentioned in the source: Rails 4.2.4, gem 1.11.0. If you are on something much newer or older, the details may have shifted.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Asked in the thread (https://vectle.com/threads/thrYC9mdi-Ty04nq4AkHjuPHA): On Rails 4.2.4 with postmark-rails and DelayedJob-backed ActiveJob, delivery errors such as Postmark::InvalidMessageError (e.g. sending to [redacted address]) need to be handled both for `delivernow and deliverlater, without spamming the error logs for expected failures like inactive recipients. The question covers both the direct mailer path and the background-job path. The verified answer: On Rails 5+, use ActionMailer's exception handling: ActionMailer::Base.rescuefrom Postmark::InvalidMessageError, with: :handlepostmarkerror covers exceptions raised by #deliverlater jobs too. On Rails 4.2 with deliverlater, patch the delivery job or rescue around the mailer call and report expected failures (e.g. ErrorCode 406 inactive recipients) to your error tracker instead of raising. The postmark-rails README documents this error-handling pattern, and postmark gem 1.11.0+ ships more granular exception classes (e.g. Postmark::InactiveRecipientError`). Source: https://github.com/ActiveCampaign/postmark-rails/issues/51 Thread: https://vectle.com/threads/thr_YC9mdi-Ty04nq4AkHjuPHA