The main reason you're no longer able to live stream video is that you've used up your monthly allotment. Yes, viewing a live video stream is a very popular feature, but it requires high amount of data usage. So, in order to manage the available monthly data, we've limited the number of minutes per camera that you can live stream.
Note: if you've used up your available minutes for the month but still need access to a live video stream, you can contact our Support Desk to temporarily override your available time for the current month (if room permits). However, to avoid this situation we highly recommend the following as a general best practice:

To conserve your available live streaming video time, we recommend that you select the live Snapshot option (which is more efficient) so you don't use up your monthly allotment to keep it available for if/when you do need it.