Use cache mode to work with items on WorldPosta mailbox, even your network connection is slow or disconnected.
Important: when using outlook with WorldPosta mailbox, we recommend using cached mode.
How to turn offline cache on or off in Outlook.
1. Click File > Account Settings > Account Settings.
2. Click on your account, then click Change.
3. Under the section, Offline Settings, check Use Cached Exchange Mode box.
4. When you finish, click Next > Finish, then exit Outlook and restart.
If you want to turn off Cached Exchange Mode, repeat the steps, but clear Use Cached Exchange Mode.
Simply, Right-click on the folder you want to clear its cache > properties > Clear Offline Items
When you finish, click OK.