<div>
Thanks for the info. &nbsp;I will contact the recipient to see if they can whitelist the sender's domain as recommended in the link provided.
</div>


Thanks for the info.  I will contact the recipient to see if they can whitelist the sender's domain as recommended in the link provided.

<div>
<div class="content wysiwyg-content">
I have a customer on Office 365. &nbsp;When they send an email to a particular recipient, they get an error:<br />
<br />
A security check at &quot;recipientdomain.com&quot; failed due to misconfigured settings at &quot;sendersdomain.com.&quot;<br />
<br />
Status code: 550 5.7.363 <br />
<br />
It appears that the recipient's email server at recipientdomain.com performed a reverse DNS (rDNS) lookup security check to verify that the IP address the message is coming from is associated with the sending domain, and the lookup failed. It appears that the pointer (PTR) record for sendersdomain.com isn't set up correctly.<br />
<br />
I know that if the sending email server is in-house, I would contact the ISP and have them create an rDNS entry but how do we fix this if the sending server is Office 365?
</div>
</div>


I have a customer on Office 365.  When they send an email to a particular recipient, they get an error:

A security check at "recipientdomain.com" failed due to misconfigured settings at "sendersdomain.com."

Status code: 550 5.7.363 

It appears that the recipient's email server at recipientdomain.com performed a reverse DNS (rDNS) lookup security check to verify that the IP address the message is coming from is associated with the sending domain, and the lookup failed. It appears that the pointer (PTR) record for sendersdomain.com isn't set up correctly.

I know that if the sending email server is in-house, I would contact the ISP and have them create an rDNS entry but how do we fix this if the sending server is Office 365?

Recipient email server rejects senders email (Office 365) due to incorrect PTR record

Within Internet message handling services (MHS), a message transfer agent or mail transfer agent (MTA) or mail relay is software that transfers electronic mail messages from one computer to another using a client–server application architecture. A MTA implements both the client (sending) and server (receiving) portions of the Simple Mail Transfer Protocol (SMTP). The terms mail server, mail exchanger, and MX host may also refer to a computer performing the MTA function. The Domain Name System (DNS) associates a mail server to a domain with mail exchanger (MX) resource records containing the domain name of a host providing MTA services.

Email Servers

The Domain Name System (DNS) is a hierarchical, globally distributed system responsible for associating the name of a computer, service or other resource into an IP address for connecting to the Internet or a private network. Most prominently, it translates domain names to the numerical IP addresses needed for the purpose of computer services and devices worldwide.

Interactions between email servers and clients are governed by email protocols. The three most common email protocols are POP, IMAP and MAPI. Most email software operates under one of these (and many products support more than one).  The correct protocol must be selected, and correctly configured, if you want your email account to work.

Email Protocols

Office 365 is a group of software plus services subscriptions that provides productivity software and related services to its subscribers. Office 365 allows the use of Microsoft Office apps on Windows and OS X, provides storage space on Microsoft's cloud storage service OneDrive, and grants 60 Skype minutes per month. Office 365 includes e-mail and social networking services through hosted versions of Exchange Server, Skype for Business Server, SharePoint and Office Online, integration with Yammer, as well as access to the Office software. All of Office 365's components can be managed and configured through an online portal; users can be added manually, imported from a CSV file, or Office 365 can be set up for single sign-on with a local Active Directory using Active Directory Federation Services.