I have a note 8 and am plagued with 'not registered on network' messages. I can't use the phone for calls or texts (not sure about WhatsApp but Internet works). It's happening daily and takes maybe 10 minutes faffing about to get back on network. My partner is also Vodafone and getting the same message but not as often (she has a S7 edge). I turned the lte option off earlier today and it hasn't happened since so I'm wondering if it is something to do with transferring from 3 to 4g....? I rang Vodafone who advised they have no network issues in my area (the fault happens at home, work and elsewhere) it's a bit of a mission to get it back on with messages like 'cannot change network' while data transfer in place and such like. It happens most often when I terminate a call try to make another call straight away. Anyone else having thus problem? Is it a handset or network problem?