The Unifi TV app is a problematic one.. Works well on some, bad on some and doesn't even run on the rest. Can't be helped as TM won't entertain. Can't blame em. Boxes are running heavily customized OSes originally designed for smartphones. Some with half-baked firmwares. So you have three options;
*Wait for an update either from TM or your box manufacturer that hopefully fixes the issue.
*Go hunting for older apks and try each one by one till one works.
*Get a box that's known to run it properly..