x500 email format on contacts

Question

_{Thursday, November 14, 2019 11:46 PM}

Hello, 

Im not an exchange adminstrator, and work on another business application integrating with exchange. A few contacts in users mailboxes for a client we are working with have an x500 value in the email1address field. We are querying this data through EWS. These contacts are not internal contacts and it looks like a sizable portion of contacts created as old as 2012 and as new as a few weeks old. These contacts are probably 0.5% of all contacts in all users mailboxes. 

A few questions on this:

1. What could have caused these contacts to be created with this email format?

2. These contacts have an SMTP address when looked at through the UI, but have an x500 address returned to us through EWS, why does this happen?

3. What is an easy way to set the email1addresses of these contacts to the SMTP format?

(We need the SMTP address for our integration) 

All replies (3)

_{Friday, November 15, 2019 6:54 AM}

Hi,

According to your questions:

1. The contacts may have other types of email addresses except from SMTP. The email addresses of user mailbox can contain more than one, which may including custom type of email address. The “x500” may be the custom type of email address.

2. As I said above, one contact may have more than one address. This problem occurs because while the Outlook auto-complete cache stores SMTP addresses for e-mail sent to external addresses, it uses X.500 addresses for e-mail sent to addresses within the Exchange organization.

Mail contacts can be created in your organization, and each contact has external email address, and all email messages that are sent to a contact are automatically forwarded to that address. Contacts are ideal for representing people external to your Exchange organization.

3. I suggest to keep the address. If the X.500 address is missing, it may cause exchange to reject the message and return an undeliver email. Please refer to the blog, Exchange Server X500 Address An Amazing Thing to Know.

Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.

Regards,

Vera Shen

Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact [email protected].

_{Thursday, November 21, 2019 1:08 AM}

Has there been any updates in solving this problem? If you have solved your problem, could you share with us? Maybe it will help more people with similar problems.

Regards,

Vera Shen

Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact [email protected].

_{Wednesday, November 27, 2019 6:42 AM}

The following is a brief summary of this issue so that others can get help from this approach.

Issue Symptom

A few contacts in users mailboxes for a client have an x500 value in the emailaddress field. 

Possible Cause

The contacts may have other types of email addresses except from SMTP. This problem occurs because while the Outlook auto-complete cache stores SMTP addresses for e-mail sent to external addresses, it uses X.500 addresses for e-mail sent to addresses within the Exchange organization.

Solution

Suggest to keep the address. If the X.500 address is missing, it may cause exchange to reject the message and return an undeliver email.

Reference Link

Exchange Server X500 Address An Amazing Thing to Know
Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.

Regards,

Vera Shen

Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact [email protected].