Someone in the comments (Daniel Rall) seems to have the same problem: https://forums.androidcentral.com/android-4-1-4-2-4-3-jelly-bean/306239-bluetooth-volume-jbl-charge.html
Will it start playing music and then stop, or does it just not work at all?
Here's another thread of a similar issue, but with a computer and a different speaker (not sure how relevant): https://superuser.com/questions/1024006/windows-10-computer-paired-w-bluetooth-speaker-but-doesnt-send-music-to-speak
You might explore your phone's settings to see if there's a music vs call setting. If the other phone you tried was an Android, it might be a new update. Otherwise, maybe open the speaker to look for damage if it's not still under warranty.