PHP Version 4.0.0.

When sending mail to more than one recipient (comma separated) all recipients are sent,comma separated, in just one SMTP: "RCPT TO" message.
The mailserver responds with "553 Invalid Address Syntax" and the mail of course fails.

There should be only one recipient in a RCPT TO message.
So when sending to several, the correct way of doing this should be to send several RCPT TO messages with one recipient in each.

Example:
$To = "someone@thecompany.com,anotherone@thecompany.com";
mail($To,$Subject,$Msg,$Headers);

The SMTP will look like this:
RCPT TO: someone@thecompany.com,anotherone@thecompany.com

and should look like this:
RCPT TO: someone@thecompany.com
RCTP TO: anotherone@thecompany.com


The problem doesn't exist in PHP3.0.16.
/Bjarne