By default, Outlook checks for new messages every 30 minutes.  Sometimes the interval is even longer if your computer is busy.  If you feel that you have new e-mails that are not showing up in Outlook, you have a few options: 
 Option 1: Set up Outlook to check for new messages more often. 
 1. In Outlook 2016, go to  File  then select  Options .  
   
  
2. The Outlook Options...
                           
                           
                               Article Id:
                                19574