Web API Transfer Playback returns 403

[mega386]

Plan

Premium Family

Country

USA 

Device

PC

Operating System

Windows 11

My Question or Issue

Following the documentation here: https://developer.spotify.com/documentation/web-api/reference/transfer-a-users-playback

In the "try it" section of that page I get a null response.

When I try it from anywhere else I get this response:  

{
"error": {
"status": 403,
"message": "Player command failed: Premium required",
"reason": "PREMIUM_REQUIRED"
}
}

At this point I've already got my Oauth token of course... 

I have Premium Family so this seems like a bug.