Outlook sent folder not updating
You also can create a new folder to move the folder into by right-clicking the parent folder you want and choosing Create new folder.
It only shows old emails that were sent untill about 1 month ago.
Your administrator may also have set up a policy to empty items from your Deleted Items folder after they’ve been there for a preset number of days.
Note: If you need to move messages out of your mailbox but want to save them, you can use Outlook and to save your messages to a file.
Career Path: Professional roles include Ethical Hackers, Security Consultants, System Administrators, and Chief Security Officers. If so, select the 'Sent Items' folder, on the menu bar select 'View', in the 3rd ribbon section called 'Arrangement' , select any view to sort by (Date, From, To etc.). As mentioned already by gerwinjanssen: Tools, Options, Mail, Save messages, check box ' Save Copy of Sent items'.
If this is already ticket, disable it and quit Outlook. Test if it works now (strangely this sometimes works).
You can also set up rules so that Outlook on the web automatically moves messages into folders depending on conditions that you specify.