problems with mail()

[benoit96]

I have have Appache, Postfix and php running on Linux. I have a real strange problem. On the forum I've created I use mail() to confirm the registration of users, but half of users never receive their confirm email.

Did anybody have an idea why ?

I'm seeding only text, no html. And I have a "From : $fromemail" header.

[dar-k]

Are users forced to fill in all necessary info?

[benoit96]

Yes they do. And I've stored the information in a database so we can email them later and if I use Outlook I can reach them, so their email are valid. The point is that the mail function seems to fail half time.