FormMail Help

[SamirM]

Hi,

I have a domain setup on my server, which has an enquiry form in php, while this form was working till about 3 days back, all of a sudden the form doesnt work at all.
The domains MX records however are not on my server, they have an external mailserver.
Debugging the logs i get the following:

["message_type":"PHPMailer"rivate]=>
string(5) "plain"
["boundary":"PHPMailer"rivate]=>
array(2) {
[1]=>
string(35) "b1_a10c8553bcea7328ccddf0e0fdb01ef9"
[2]=>
string(35) "b2_a10c8553bcea7328ccddf0e0fdb01ef9"
}
["language"rotected]=>
array(17) {
["provide_address"]=>
string(54) "You must provide at least one recipient email address."
["mailer_not_supported"]=>
string(25) " mailer is not supported."
["execute"]=>
string(19) "Could not execute: "
["instantiate"]=>
string(36) "Could not instantiate mail function."
["authenticate"]=>
string(35) "SMTP Error: Could not authenticate."
["from_failed"]=>
string(35) "The following From address failed: "
["recipients_failed"]=>
string(45) "SMTP Error: The following recipients failed: "
["data_not_accepted"]=>
string(30) "SMTP Error: Data not accepted."
["connect_host"]=>
string(43) "SMTP Error: Could not connect to SMTP host."
["file_access"]=>
string(23) "Could not access file: "
["file_open"]=>
string(33) "File Error: Could not open file: "
["encoding"]=>
string(18) "Unknown encoding: "
["signing"]=>
string(15) "Signing Error: "
["smtp_error"]=>
string(19) "SMTP server error: "
["empty_message"]=>
string(18) "Message body empty"
["invalid_address"]=>
string(15) "Invalid address"
["variable_set"]=>
string(30) "Cannot set or reset variable: "
}
I am on a CentOS 6.2(final) server with Plesk v 11.0.9,
appreciate any help

samir