The Incident Deletor fails when incident(s) to be deleted are associated to a Message that has ProxyMessageInfo record(s).
The Incident Deletion Progress web page may show the following error for the 'Failed' status:
Error Message: ORA-02292: integrity constraint (PROTECT.PROXYMESSAGEINFO_FK1) violated - child record found
Release : DLP 16.0, 16.0 MP1
This has been fixed in 16.0 MP2 and higher.