Imap account : root folder

Manually enter INBOX in all caps, or go to server settings and change 'root folder path' to empty
If it doesn't work, use this
1. Force the path to be specified: Fill in Account Settings→Advanced:

Root folder path: INBOX.  
2. Server check: Test IMAP level with Telnet:

bash
telnet imap.server.com 143  
LIST “” *  
3. Registry nuke: Modify the RootFolder key value of the corresponding account under HKCU\Software\Microsoft\Office\16.0\Outlook\IMAP"”