You are backing up data to a network share, and Validation is enabled in the backup plan. A recovery point is created, however, during the validation operation the target network share became temporary unavailable.
The process hangs at 89% and you see an "Interaction required" message in the Status column. When you click the activity to see details, it says: "Network location is unavilable at the moment". When you click Retry, it gives you an error message: "Cannot resume a command because it is not paused".