The first things to check are if emails are in the Junk folder and ask if the user has any automatic email rules for moving emails to specific folders.  In the case that neither of these issues are the case, more in-depth troubleshooting is needed.

Here are two useful ways to track down where the break is happening in the chain of the email connection.

Item 1: Send Test Email to Email Address Having the Problem –

This will determine if an email forwarding rule is being used and if the remote server is receiving the email.

1. Send a normal email to the person/system email address having issues.  Before sending the email, select from the top menu, Options.  Choose the following: 

Request a deliver receipt     -- this option will give an email back that the email was delivered to the server and the users email box. It means email is working. (useful when there is a firewall or remote email server rejecting the email type issue)

 Request a read receipt.       –   this option will give you an email back when the receiver of the email has opened the email and is reading the email.  (useful when checking for email rules, emails going to junk, etc.)

In situations where there is an email being sent to a generic email box and then forwarded to another email box, the delivery receipt will have one email name but the read receipt will have a different email name.  For example, Registration@colostate.edu email box is the generic email box that is auto forwarded to Registrars_Office@colostate.edu.  When the forwarding rule brakes between the two, the email sent to each email box had different response in that Registration@colostate.edu did get a delivery receipt, but Registrars_Office@colostate.edu did not provide a read receipt.  This tells you that the forwarding of email is broken.    

Item 2: Read Internet Headers for Error Code - 

The SMTP protocol provides a WEALTH of information. This log the protocol provides is by default and makes troubleshooting so much easier.  

To access the SMTP log, in Outlook, double click on the email of interest to open the email up.  

1. In that email, select the File menu.  

2. On the right-hand side of the email that pops up choose: Properties. 

3. In the Properties window, in the Internet Headers box, look at when the email was sent, when the email was received, who the email was sent from, what email server sent the email and what email server received the email, etc..

Important Point: SMTP protocol includes a lot of useful information.  If you scroll through this log of details, if the SMTP protocol/email servers have an error, errors are listed under the server’s name.  You can Google that error code to understand what the problem is.  

Note of Caution:

Each server in the chain of sending and receiving emails has to accept the email address as a valid email address.  In most cases, this is true as a default setting.  In some organizations, there is an additional level of security in which an "allow email from" list is added as a filter to all emails coming into the system.  If the email address is not recognized or allowed, the email is dropped.  This happened with Larimer County for Keri Rollins.  We had to call Larimer County IT team and have them add Keri Colorado state email address to the allow list.