If a document was submitted with a workflow requiring approval from a specific user role, but no user was assigned to that role at the time, the document will not route correctly.
Solution:
You will need to cancel the current authorisation and make sure the user role has been properly assigned before resubmitting the document for approval. 
 This ensures the document is routed to the correct user, as the original workflow was based on the configuration at the time of submission.
The user can cancel the documents approval process by clicking cancel from within the document. 
Alternatively an admin user can cancel the authorisation from the pending authorisation screen.