If you set up the workflow so that assigning an agent is not required, the system is not able to send any messages if errors occur. As a consequence, the results of mass processing (mass changes, mass retirement, mass transfer) are not visible. When this happens, look at the worklist (Environment → Worklist → Display) and start the report by entering the number of the worklist. In the list you see the status of the worklist, which is shows that it has errors. Then choose Edit → Display errors in WL to analyze the errors.