SuperUniti - N-Stream - Server not responding

Hi all.  Over the past few weeks whenever I select 'library' on the N-Stream app I get the error 'Server not responding'.  If I close the app and reopen, it seems to temporarily resolve the problem.  However this is far from convenient.  Would this be an issue with the SU, or perhaps the UPNP server Minimserver, or even a network issue?  I can't seem to figure it out

Any suggestions would be very much appreciated.