Oracle 12c - Insufficient Privileges When Trying To Create A Trigger With SYS User

I want to create a trigger for CRE schema. I'm trying to create this trigger with SYS user but I have insufficient privileges error. My trigger: CREATE OR REPLACE TRIGGER CRE.TRIGGER_NAME AFTER LOGON ON DATABASE DECLARE asd1 NUMBER; asd2 NUMBER; asd3 NUMBER; asd4 NUMBER; asd NUMBER; qwe VARCHAR2(200); qaz VARCHAR2(200); ewq NUMBER; zaq VARCHAR2(50); xsw VARCHAR2(50); BEGIN CRE.SOME_PROCEDURE_NAME('S', SYSDATE); END; / How can it possible with SYS user? How can I fix it? Best regards.