Hi @IBN ,
There are many scenarios that can prompt one of this message. The most common cause is that permissions for the user or administrator are configured incorrectly or not configured at all.
You can test whether the user only has access to this item or all items in the entire list.
If it is the first one, you could check the permission of this item:
If the items in the entire list cannot be accessed, you can go to List settings>Permission for the list to check the user's permissions. If the permissions are incorrect, reset the permission:
Customize permissions for a SharePoint list or library
For more information about permission levels in SharePoint, you could refer to:
User permissions and permission levels
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