You can always test mail acceptance using telnet. Example:
Code:
# telnet mailin-03.mx.aol.com smtp
Trying 64.12.137.249...
Connected to xa.mx.aol.com.
Escape character is '^]'.
220-rly-xa04.mx.aol.com ESMTP mail_relay_in-xa4.4; Mon, 21 Mar 2005 02:49:55 -0500
220-America Online (AOL) and its affiliated companies do not
220- authorize the use of its proprietary computers and computer
220- networks to accept, transmit, or distribute unsolicited bulk
220- e-mail sent from the internet. Effective immediately: AOL
220- may no longer accept connections from IP addresses which
220 have no reverse-DNS (PTR record) assigned.
helo mydomain.com
250 rly-xa04.mx.aol.com OK
mail from: <>
250 OK
rcpt to: <jsmith@aol.com>
250 OK
quit
221 SERVICE CLOSING CHANNEL
Connection closed by foreign host.
In this case, the 250 OK tells us everything went fine. A code in the 500s means a permanent failure, and a code in the 400s means a temporary failure.
If I had to guess what your problem is, I'd say it's the reverse DNS that the greeting says may be required. Do you have reverse DNS set up?