Issue Definition 

 SharePoint Site Calendar does not sync with outlook. When you try to sync the SharePoint Calendar, it throws following error: 

Task ‘SharePoint’ reported error (0x80004005) : ‘An error occurred in this SharePoint List (Enterprise AIX Computing – Team Calendar). Try updating the folder again. If the problem continues, contact the SharePoint site administrator.  

HTTP 500.  

The server returned the following error message: The attempted operation is prohibited because it exceeds the list view threshold.’ 

Cause:

List view threshold for SharePoint Calendar list exceeded.

Resolution:

  • We observed that the SharePoint calendar in which sync is failing at more than 5000 items in it (5300+) 
  • Suggested you to delete some items from this Calendar list, as in SPO items in calendar cannot cross the threshold of 5000 items.  
  • We then went through the process of deleting items from this calendar list.  
  • Everything is now working as expected and you will be deleting more items as at your convenience later.