G80 does not save

My G80 has worked fine for the last 2 years. Now it won't save - having never had this issue before. After a round I select 'save'. When  syncing my iphone though the Garmin Golf app the round does not appear despite syncing fine. I have removed and reconnected the G80 through the app - but still no joy so I think this is a G80 saving issue rather than a syncing issue.