Midi controller stopped working in Elements 11

Hi All, I’m new to Cubase 11 Elements having just upgraded from Essential 5. Having set up all the parameters I could find started working fairly successfully, but now the midi connection between my controller and Cubase has stopped working, so I cannot record VST instrument tracks. I set it up using a Yamaha PSR-500 as the controller, selecting the nearest device match in the options in Device manager - in this case the Yamaha PSR-530-630-730 option. At first this worked fine, and as long as I switched on the keyboard before I booted up my computer it worked fine. Now it has stopped, and having gone through all the settings several times I can’t find anything wrong. Can anyone please help?