Outlook Inbox Not Updating automatically could be caused by a number of different things. We have mentioned the reasons for these that are obvious and indicate an error.
1- You have corrupted or damaged OST files on your PC.
2- There's a chance your PST file is damaged or corrupt.
3- You can't use your auto-update function.
4- Your inbox's updating speed is sluggish.
5- An internet connection to the Exchange server may have been lost as the cause.
6- The items that are offline and online do not synchronize properly.
