The standby mode on your Freesat box might be set to an energy-saving one, which is known to generate that message when the box is first turned on.
Press Home on your remote, then Settings, then System settings, then Standby mode, then Set Standby Mode. Change the mode from Passive to Active, then Save & Close.
That should solve your problem. However, as Active standby mode uses more electricity than Passive mode does, it'll probably also add about twenty quid to your annual electricity bill!