Sending an email via workflow to a distribution list

We have a When New Record Saved workflow that sends an email when the Workflow Rule Condition is met.  We've validated the Workflow Rule Condition is working properly.  We also validated the Action to send the email works as expected when sending it to a specific individual users email address (To field = Specific Email Address with 'abc@123.com' entered as the valid email address).  However, when we put in an outlook group email address the messages are never received by the members of the group.  We tested the outlook email group by using the specific email address via outlook 'group@123.com'