When there are some missions near, it does not enable the button to load more
In the example I know there are more missions in 8 or 9 km
We should know what are the limit in km or how many mission is the limit to display
The Ingress app will load nearby missions, with nearby defined as approx 8-9km. You should be able to use Intel Map at https://intel.ingress.com/intel to view missions further away from your current location.