Hi @Potsdamer
Would be great if you can share the outcome of the support ticker, since I have the same issue.
Thanks
Angelos
Hello,
You can do that from play.volumio.com
Once you are inside the UI click on PLAY HERE button
Davide
VOLUMIO TECH SUPPORT
My Problem is…the “PLAY HERE” Button don´t work…is not activated… I don´t now…
Go in sources menu. Enable multi room if needed, in multi room settings, scroll down to enable browser playback.it should enable what you want 
Evening @balbuze
I have ‘enable browser playback’ not enabled, and yet I can play remotely via myvolumio.org … or is that only for the play.volumio.com option? And do you know if there’s a difference between the two?
Simon
Enabling this in multi room settings, disables the option to play on the machine USB where volumio is installed and still does not make available any PLAY button when remote on the mobile and outside my lan, either on myvolumio.org or play.volumio.com
Have you registered your Volumio device to your premium account?
It seems to me that’s what you’re missing, that’s the only way the green arrow appears.
For me it looks like this
Volumio devices that are not registered to MyVolumio Premium or are switched off do not have a green arrow.
You have a lot of systems!
Yes:-)
Not all of them are in operation anymore, some of them are currently in storage. 
Since you obviously have Premium, create a support ticket so that they can take a deeper look at your issue.