Some Outlook settings are need to be adjusted. Outlook keeps the mail offline for a certain period of time(this is one of the property of Outlook).
Old mails may get removed from offline state and may be then your issue arise. Well follow this simple procedure to make the adjustment :-
- Open Outlook
- Go to File > Account setting
- You will see a window with your email address > Double click on the panel
- You will now see option “Keep Mail Offline” > adjust according to you > Save & Restart Outlook.
This will resolve your problem & even if the issue persists ,feel free to ask any further query .
Thanks & Regards