I followed this tutorial on configuring the Rails plugin ExceptionNotifier.
I know that I have ActionMailer configured correctly because I am getting mail from other forms. I even have local_addresses.clear set so that it should be delivering mail no matter what.
I am using Apache with a mongrel_cluster running in the backend.
What am I missing?
You're using the SVN version of the plugin, which is probably unmaintained. Latest version can be found here.
Second thing which you can do is check the production log. Mailings get written to the log, so you'll see if Rails ever even tried to send it. If there are no entries, that means things are silently failing, which probably happens because -- for some reason -- exceptions are not caught properly.
Check your production log, exceptions can be throw in side the exception_notifier plugin, which prevent it from sending mails
If you added your ExceptionNotifier configuration information (your email address, etc.) into config/environment.rb, did you add it within the Rails::Initializer block or did you add it at the end of the file?
The tutorial you linked to doesn't specify where in the environment file to put the configuration information. The tutorial I followed (which might have been this one) does specify to put it outside the block.
Which things go inside that block and which outside is, frankly, still a little mysterious to me. But I thought this might answer your specific question.