Notify PO Approver stuck at the activity "Wait for Concurrent Program"

 Dear All,

For few POs, Notify PO Approver sub process is stuck at the activity  "Wait for Concurrent Program" and notifications are not sent to user.

I could not much information from Status Monitor screen.

I do not have workflow builder installed in my machine to open and check the workflow.

Could any one please tell if there is a way to check the concurrent program for which workflow is waiting for and what actions to be taken?

Regards,

Sreekanth