NameError: uninitialized constant Mail::Parsers::ContentTransferEncodingParser

Question

Sometimes when I send mass email on heroku some of them fail with the following error: NameError: uninitialized constant Mail::Parsers::ContentTransferEncodingParser

I have no idea why is that but I think that maybe this maybe caused by using attachments.inline in mailer. Any ideas what may cause this problem?

Answer 1

I create initializer with following line:

Mail.eager_autoload! if Rails.env.production? && defined?(Mail)

and that fixes the problem.