Some of my contacts say that they didn’t receive the email I sent out.  What happened?
If a contact reaches out to you, claiming that your email wasn't received,
here are some things that you can check:
(right-click and choose 'View Image' to view a larger version)
1) Make sure the contact isn't unsubscribed, and that he/she has a valid email address.

Go to the Contacts page (fourth icon, first link) and search for the contact by email address in the top right.  When you find the record, double-click to open the Contact Details window.  

You'll see a series of links at the top of the window; click on Preferences.  You can view/change subscription preferences at the email category level on the left side (email category changes don't require saving), and global status on the right side.  Also found on the right side is the email address status.  If it's marked as invalid and you know that it's a good email address, you can click the Reset Status button.

NOTE: If you see 'No Status' by an email category, it simply means that no action has been taken either way (i.e. the contact has chosen neither subscribe nor unsubscribe), and the contact is opted into that category by default.

IMPORTANT: You are NOT allowed to change subscription preferences without permission from the contact.

2) Look at the contact's Activity Log.

With the Contact Details window still open, you can click on the Activity Log link in order to view activity such as email sends and opens, website visits, and unsubscribes (global only).  The type of activity can be narrowed by choosing a different option in the dropdown menu, and a date range can be set (up to a year).

This window is useful for determining whether or not a contact received and/or opened an email, and if there was an unsubscribe preference chosen at some point.

3) Check the VIP record to see if there's a different 'preferred' email address.

If you have VIP access, it can be useful to look at the contact's VIP record to find out his or her 'preferred' email address, as the preferred address is the only email address synched from VIP to Eloqua. (There have been many cases in which a contact expects to receive UT email at a certain address, but isn't aware that a different address is actually marked as preferred on the official UT record).

4) Check if the contact was Excluded from the Campaign or Email Step.

A contact can be excluded from a Campaign or Email Step for one or more reasons.  If a contact is excluded from the Campaign or Email Step, they will not receive any communications in the Campaign or will not receive the email in that Email Step.  To identify if and why a contact is excluded, check the participants information.

For more information on how to resolve common Exclusion reasons, click here.
In a simple Campaign, click View Participants and select the Excluded tab to see a list of all the contacts in the Segment that were excluded by the Campaign.

In a multi-step campaign, double-click the number in the email step to see a list of all the contacts in the Segment that were excluded from that Email Step of the Campaign.