Ok thanks, next thing to check is that the TX has exactly 500 coins (enable coin control in settings if you haven't already, then go to Send -> Inputs. ) There should be a single transaction (1) with 500 coins.  Double check the TXID of that transaction matches whats in your masternode.conf file. 

Try starting the node again, then run ./craved masternode debug and see if the output is any different?