User gets a "PreventCache" or "502" error when tying to view a large multipage file in Brava.
The problem is caused by the IIS server farm closing the connection to the Brava server has responded that the render is complete. Since the Brava server hasn't responded to the request, the IIS server throws the 502 error.
Open IIS Manager, select the BravaServer server farm, and click on Proxy in the center pane. Set the Time-out value to a higher/desired value and click Apply.