I have successfully set up email notifications on my client's blog for administrators when new comments are posted and am now trying to set it up to send a thank-you email to the poster of the comment as well. I set it up using triggers and actions as described here.
I put in
[comment:author:mail] in the "Recipient" field on the action configuration form as suggested in the note right below that field, but it seems that it never sends the email. I initially tested it using my own email address and it worked fine, then I posted a comment as an anonymous user using two different email addresses of mine but never received an email. Why is
[comment:author:mail] not working? I'm using other variables in the body of the email (e.g.
[comment:node:title]) and they're working fine.
I tried using Maillog as @tenken suggested below, which verified that the problem isn't with mail delivery but rather with the email not being populated correctly:
Here's a screenshot that shows the email to the administrator is working correctly, but not the thank-you email: