Receiver does not get email sent via mail() and php mailer

php mailer and mail()

[simon2006]

I am encountering a really weird problem

Have been sending emails via php's mail() and also php mailer.
It successfully sends to and received by every email address I have used.

There is one case though for a particular email address, where the email is sent successfully but never received at the other end.
Then using gmail or whatever, I send an email and it is received perfectly?

Anyone had a similar problem?

(The only possible thing that could be different is the fact that the email is sent to an address which is checked via POP and ends in ".com.au")

Also, no, the message is not filtered into spam

[simon2006]

Oh, I forgot to include it is over an SSL connection...........

[jatar_k]

Welcome to WebmasterWorld simon2006,

if it is only a single address on a specific ISP then I would look at differences with that particular ISP.