My garmin Fenix 6 watch won’t record stress and body battery.

My garmin fenix Watch has stopped measuring/ recording body battery and stress levels for the last 2 days. 
Nothing has changed on my settings and it is still on the list of display items under ‘my day’. There is also no data on the watch widget for both stress and body battery. 

Any ideas what has happened to these and how to get this working again?