I use a workflow with a send email action to send out our customer statements. The workflow is scheduled and the customer list is dynamic based on a saved search. 3 different customer records all with the same email address were on the saved search output but only 2 of the customers had an email for the statement of account sent. Given the email address was not on the bounced or undelivered list and the workflow worked for 2 out of the 3 customers I am not sure what steps to take to identify the issue for the 3rd customer who didn't receive the email.