Kindle Fire HD requires activation while Android doesn't?

I am the plex server owner, and I have a lifetime plex pass.

I have a few friends using Android devices that are able to login with their normal (non plexpass) user accounts, and stream content from my server.
However, one friend using a Kindle Fire HD is getting a message that he has to activate the app for $5 or sign in with a plex pass.

Anyone know what is going on here? Why can my android friends stream no problem buy my kindle friend can’t? Is this expected? It seems that adding him to ‘my home’ may be a fix, but I’d rather not set all that up when I haven’t thus far.

“Android TV” devices get the Plex app for free. (Amazon Fire TV, nVidia Shield, tv devices running “Android TV” )

The Kindle Fire HD however is a regular Android (without “TV”) device.
The Plex app for this is available for either a one-time fee (about $5) or it is also included with a Plex Pass.

Thanks for the response. I went back and talked to my Android friend, and found that they did actually pay for the app in the first place. I thought they didn’t - my bad. Thanks!