Relaying an internal PHP application by Exchange 2013

Question

Hello, dear Fellows,
We use an Exchange 2013 server
to relay two web applications via a Front-End Transport Receive Connector, properly configured.
All messages sent by the ASP Web Application, are received
by all the recipient domains.
But somes messages sent by the PHP Web Application are not received
by some Domains, remaining within the queue, with error messages:
554 5.4.4 SMTP.SEND.DNS.NonExistentDomain;non existent domain
451 4.4.0 Primary Target IP responded with 421 4.7.0 "ServerName" Too many errors "Cannot achieve “Exchange Server authentication”.” Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery
failed to all alternate hosts…"
Do you think this is a PHP problem, or an Exchange problem ?
Thanks for your answers
Djamal Belouizdad
Exchange Administrator

Answer 1

Hello Djamal,
I do not know if it's the right answer, but I'll
tell you about my problem and how we solved the
problem.
We had a problem with two sites developed
in PHP, when we send emails from applications
in PHP, recipients receive the email
but with an empty corp.
We just added a new line (un saut de ligne PHP <br /><br />)
at the beginning of corp email.
before the modification:
$Body="Bonjour,<br /><br />
            Vous avez reçu un fichier .......<br /><br />"
after the modification:
$Body="<br /><br />
Bonjour,<br /><br />
            Vous avez reçu un fichier .......<br /><br />"
Thanks
Samir TABTI
Administrateur Réseau et Système (AXONES)