Perhaps you're having same problem as me, its not too big of a problem just annoying. Mine is set to standby when I turn it off. If I either don't access the Live TV app for longer than a day or I don't turn on the box for more than a day, I get the same as you no response from server. I simply press the Power button on the remote and hold it down so it gives me the option to restart. Then I'm able to access my provider without needing to change mac or factory reset. I still need to test recording but if you're going to record I would do a restart first just to be safe.

There is an option in Live TV settings to set when Live TV app shuts off, thereby saving bandwidth, something like shut it off after 4 hours, etc.

I have a BuzzTV XPL3000. I leave the box when the IPTV app is not in use set to the home screen. In this mode, it's not using any bandwidth. I also installed Keep Screen On from the Google Play store and set all other screen/power options to stay powered on for instant access.

If you change the MAC is won't work unless you give your provider the new MAC.

Otherwise, I'm not sure that I understand exactly what the issue is.

I have this device and not experiencing that issue. Provide a bit more context as to why you are changing you MAC both server side and on the device so we understand.