One reason emails may not be showing in Outlook is due to some folders not be set to synced/subscribed.

Instructions may vary depending on the device and version of Outlook you are using.
If you require additional support for Outlook, we recommend reviewing the support resources provided directly from Microsoft:  https://support.microsoft.com/en-au/outlook 

1. From your inbox, for the email account in question. Right click on the Inbox folder, then select IMAP Folders...
   
   
   
   
2. Select Query
   
   
   
   
3. Select all folders then select Subscribe
   
   
   
   
4. Select OK
   
   
   
   
5. From the menu select Send / Receive
   
   
   
   
6. Select Send/Receive All Folders