Changed the radio station and after that the button had disappeared.
I can still see the "Press" and it works, just the button has vanished.

Button came back some time after.
I also notice that sometimes the radio stops.
Pushing the button twice turns it on again.

This is first public version of this plugin the button does remove itself visually however remains fully functional without being visable

this will be fixed in next patch

Same issue with button.  Glad to hear a patch is coming. 
My players are loving this plugin.

FYI, Just updated with the recent release (deleted old config as instructed), and the button still disapers.