There may be a report created in the Enforce console by one of the administrators which is still sending e-mail notifications. However, none of the current Enforce users are able to find the report in the UI. It might be that the report is owned by a user or role which is not an active Enforce user anymore and no one can recall which one it is.
The goal is to locate the report and its owner to be able to then find it in the UI.
If you know a report's name, you can locate it in the DLP database via Oracle. You can connect to the DLP database via SQL Developer and look for the report using the below SQL queries as basis.
SELECT NAME, PERMISSION, USERID, ROLEID, TYPE, CREATEDATE, REPORTEMAILSCHEDULEID FROM REPORT WHERE NAME LIKE '%Report name goes here%';
SELECT NAME FROM PROTECTUSER WHERE USERID='ID from query 1 goes here';
SELECT NAME FROM ROLE WHERE ROLEID='ID from query 1 goes here';