I'm using the Android app provided by my provider ( a Smarters branded I believe) and sometimes get freezing and buffering.
Not being to familiar with the apps or Android boxes in general, is a blue spinning circle during buffering usually my local network or the provider? Or can it be both?
Download one of the speed test apps and see what your device gets. I get a lot of buffering with anything below 35MB/s, the occasional buffering I still get now at 70MB/s is due to my IPTV provider. So if it turns out your box can only do 10MB/s then it's probably all you.