I am using 7820A GC coupled with 5977B Mass Spec. After use I close the He tank and later on I get 2 messages - 'Front inlet flow shutdown' and 'Front inlet pressure shutdown'. I restarted the software but it fails to load any GC method and the flow shutdown problem also persists even after opening the He gas tank. The GC oven temperature become 25degC. Could you help me with this?