Disney+ unstable at best, doesn't load at worst.

I have a 20mbit wisp out here at my home. We have almost flawless streaming regularly. 2-3 people plus myself running online games daily and often at the same times. However while these things work with no hiccups to speak of when my wife tries to run Disney+ which is on the smart tv it just fails. The Disney+ client loses connection regularly, the stream buffers a ton. The rest of us have no problems. I never get lag spikes on my games. I ask my folks about their streaming, no buffering or anything pretty much ever?

I'm just lost. I know 20mbit isn't much these days but for now the best available where I live. Why does everything work fine except the Disney+ whether or not anyone else is really streaming or anything?