Troubleshooting Calendar Sync Delays Between Outlook and iPhone

User: VIP and his secretary

There are 3 scenarios, I am not sure if this is Apple issue or Microsoft issue..

1. Sometimes, when the secretary modifies the VIP's calendar in Outlook (PC), the new date/time update successfully,

but Outlook continues to display the old date/time. These changes do not immediately reflect on the VIP's iPhone calendar. However, after some time, the synchronization between Outlook and the iPhone calendar functions correctly.

2. At times, the secretary fails to modify the VIP's calendar in Outlook. The secretary must try several times before the changes take effect.

3. When the VIP modifies his Outlook calendar directly, it also takes some time for these changes to synchronize with his iPhone calendar.

 Please help to provide solutions.