Workflow stopped Error after submission for approval in Ax 2012

Problem.

I faced this error Workflow stopped Error after submission for approval in Ax 2012.

The items are Purchased, Received or Registered. Quantity ordered cannot be reduced because there are not enough open stock transactions with the ordered status.

Observation

My observation is as below

When I am create new Purchase order and purchase order is in invoiced status but 2 qty is in cancel mode then purchase order getting approved but for old order its give above error.

After investigation on google and other sites I did not get anything so finally I did approved workflow from back end activity.

I hope some people who is smart they will give answer to me on this query.

After some days I get same error again then I assigned admin rights to approval user then its getting approved.