This worked for me too after lots of hair pulling.

Note the difference between:

Log::Dispatch::Email::MailSender

in the working example, and:

Log::Dispatch::Email::MailSend

in the original, which I also had from somewhere on the web, but was unable to get to work with SMTP, although it does not error, it just writes to mailer.testfile instead.

Also that:

log4perl.appender.Email.smtp = smtp.z.com

is the correct way to specify the server, at least this works for me.