Help using ARMailer

I get this error after trying to send an email:

can’t convert nil into String

I only have one model to send emails:

class MyMailer < ActionMailer::ARMailer

I have put this in config/development.rb:

config.action_mailer.delivery_method = :activerecord
require ‘action_mailer/ar_mailer’

Where is the problem?

I think the problem is located in ActionView/base, so thats what my log

I hope you’ve found a solution by now but I got the same error until I
double checked the model I was associating with ARMailer and found I
had it pointing to my personal email-forming class, not the blank
Email class ARMailer desired. Once that was corrected, the error went
away and I’ve been firing emails with no problem.

On Mar 20, 2:43 pm, John S. [email protected]