I followed step by step the reimbursment workflow tutorial provided by Ananya Chatterjee and the flow engine isn't able to set the request at the suitable level due to the following error.
ORA-20987: APEX - An attempt to create a task for task definition 42607999452093972928 in application XXX failed because the task definition does not contain any potential owners - please edit the task definition and add at least one participant of type potential owner - Contact your application administrator.
My task def. is the following
