The attachment size exceeds the allowable limit.
Not able to delete the calendar Items , please follow the below method. Use MFC Mapi to delete the calendar
a) Please Launch MFCMAPI tool on the user’s client.
b) Go to Session -> Logon and Display Store Table.
c) Select the outlook profile of the user and double-click “Mailbox - your user name”
d) In the next window->expand “Root Container”