Problem in CC BPM in PI

Hi Team

We are facing a strange issue in CC BPM. For some of the messages, one send step in BPM remains in "InProcess' status for a long time ( more than 2 hours)

When I try to find out the problem , I see this message in SWWL

'

Work item 000000189474 cannot be executed in status STARTED'

Can somebody help me to solve this issue. Any help will be highly appreciated.