ORA-28004: invalid argument for function specified

CREATE OR REPLACE FUNCTION check_password_blacklist (

    p_password IN VARCHAR2

) RETURN BOOLEAN

IS

    v_blacklisted_count NUMBER;

BEGIN

    SELECT COUNT(*)

    INTO v_blacklisted_count

    FROM TESTUSER.BLACKLIST_PASSWORDS

    WHERE INSTR(LOWER(p_password), LOWER(password)) > 0;


    IF v_blacklisted_count > 0 THEN

        RETURN FALSE; -- Password contains a blacklisted string

    ELSE

        RETURN TRUE;  -- Password does not contain any blacklisted string

    END IF;

END check_password_blacklist;

/

Error is

SQL> alter profile test limit PASSWORD_VERIFY_FUNCTION CHECK_PASSWORD_BLACKLIST;
alter profile test limit PASSWORD_VERIFY_FUNCTION CHECK_PASSWORD_BLACKLIST
*
ERROR at line 1:
ORA-28004: invalid argument for function specified in PASSWORD_VERIFY_FUNCTION