Deleted iexpense claim still sending notification

A user deleted an iexpense claim, but still getting notifications regarding the deleted iexpense claim. When the user tries to open and view the received notifications,
the following error message displays: “An unexpected error has occurred, please contact your system admin”.

Any known reason what could be responsible for this and how it can be resolved?

Unfortunately,the expense claim cannot be queried with its number in the expense report search page.

Thanks,

Edwin