Listen Everywhere doesn't work with Bose Portable

[kencopen]

Hi, I just got a Bose Portable (Darkstar in the image) and can play Spotify through it fine, but when I try and use Listen Everywhere, music only plays on my Amazon Echo devices. Any suggestions on how I might be able to get my Bose Portable into the "Everywhere" mix?

Plan

Premium

Country

U.S.

Device

(iPhone 8, Macbook Pro 2017)

Operating System

(iOS 10, Catalina)