Upon completing the challenge for "Chatter Basics- Approving Records from the Feed" I keep running into an incomplete error.

"Challenge Not Yet complete...here's what's wrong:
There was an unexpected error in your orf which is preventing this assifgnemtn scheck from completing:
System.DmlException: Process failed.  First exception on row 0; first error: NO_APPLICABLE_PROCESS, No applicable apprival pricess was found.:[]

My mentor and I both have attempted several variations but have not been able to achieve completing this task.  Any insight?  Thank you!