I'm trying to get c5 to send an email to another smtp server. It's Exchange 2010, and I always get this exception in the logs.

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Mail Exception Occurred. Unable to send mail: 535 5.7.3 Authentication unsuccessful

#0 /home/fowlervi/public_html/concrete/libraries/3rdparty/Zend/Mail/Protocol/Smtp/Auth/Login.php(95): Zend_Mail_Protocol_Abstract->_expect(235)
#1 /home/fowlervi/public_html/concrete/libraries/3rdparty/Zend/Mail/Protocol/Smtp.php(217): Zend_Mail_Protocol_Smtp_Auth_Login->auth()
#2 /home/fowlervi/public_html/concrete/libraries/3rdparty/Zend/Mail/Transport/Smtp.php(196): Zend_Mail_Protocol_Smtp->helo('localhost')
#3 /home/fowlervi/public_html/concrete/libraries/3rdparty/Zend/Mail/Transport/Abstract.php(348): Zend_Mail_Transport_Smtp->_sendMail()
#4 /home/fowlervi/public_html/concrete/libraries/3rdparty/Zend/Mail.php(973): Zend_Mail_Transport_Abstract->send(Object(Zend_Mail))
#5 /home/fowlervi/public_html/concrete/helpers/mail.php(227): Zend_Mail->send(Object(Zend_Mail_Transport_Smtp))
#6 /home/fowlervi/public_html/concrete/blocks/form/controller.php(340): MailHelper->sendMail()
#7 /home/fowlervi/public_html/concrete/models/block.php(283): FormBlockController->action_submit_form()
#8 /home/fowlervi/public_html/concrete/startup/process.php(223): Block->passThruBlock(Array, Array)
#9 /home/fowlervi/public_html/concrete/dispatcher.php(235): require('/home/fowlervi/...')
#10 /home/fowlervi/public_html/index.php(2): require('/home/fowlervi/...')
#11 {main}
Template Used: block_form_submission
To: outflow@XXXXXXXXXXX.org
From: administrator@XXXXXXXXX.org
Subject: Sandbox Test Page Form Submission
Body:
There has been a submission of the form Sandbox Test Page on through your Concrete5 website.

test
blah

ericwright17
 
ericwright17 replied on at Permalink Best Answer Reply
ericwright17
Ok, after an exhaustive week of Google searching, I found the error buried out in cyberspace. I'm going to add it here so hopefully it can help someone else.

"535 5.7.3 Authentication unsuccessful" is an error given by Exchange 2010 meaning that the user does not have ms-Exch-SMTP-Submit permissions.

I knew this and how to add those permissions, but what I did not know was that ADMINISTRATORS can be granted these permissions but they NEVER take effect. You must create a not administrative user (I believe not Domain Admin) and use them for external SMTP authentication.
cwalker replied on at Permalink Reply
Can you please explain this in layman's terms? I am getting the same log from my submission form. However, my form is going to my Gmail account.

Any thoughts on this?