SMF Emails are not spam !!!

[rostamiani]

Hi
I installed SMF 2 RC3 But all emails that are sent from my forum will be recognized as spam !!!
SMF sends Emails with PHP method ...

How Gmail and Yahoo recognises the spams ?
Then new users cannot register in the forum because they cannot find the verification email 

What should I do ?
Thanks 

[JBlaze]

It could be that your server/host is blacklisted.

Ask your host.