In Stockouts report the processing period filter require to provide full period name, but it should instead search for records containing the provided string.
1. Go to "Reports" -> "View reports" -> Stockout
2. There should be some data available - if not:
Create, Authorize and Approve a requisition with at least one product (if there is no previous requisition data)
Run processors groups on the NiFi, so the data will be fetched to reports
3. Type substring of one of the available processing periods in "Processing Periods" filter
The records with processing period containing this string are found.