Workflow stopped error(no message, AX 2012)

Good day.

I designed some workflows on Purchase requisition, Proejct budget in AX 2012. Those workflow are composed of  elements such as Conditional decision and  Approval.

After setting, those workflows previously worked properly. But, unfotunatly it did not work correctly. It just stopped during creating the workitem. 

Actually it showed only the "Workflow Activated" and some elements such as Parallel decision was processed but the workitem for approver assignment i was not created with error messag just like 'Workflow stopped  (error)".

Can somebody help me on this error? Thanks.