At long last I have solved this problem. It was nothing to do with the Pi or max2play. It was a dodgy connection on an Ethernet plug that I used to connect the device to my router. It had been in place and working for over 10 years, but then started to work intermitantly. When it chose to work and when it did not led me down all sorts of pointless routes. e.g. it often did not work on my new Pi, then it always seemed to work on my old Odroid, so I thought the Pi was dodgy. Then I got a new Pi and it always seemed to work again, which confirmed my view that the old Pi was dodgy. Then the new Pi went off line after my wife did some cleaning and moved the wires; that finally led me to diagnose the problem. A quick squeeze with the plug crimping tool and we were back in business.
Just how many hours have I wasted …..