Web App player for players are giving them access to the master control portal. All my players now can stop music, start music, edit, adjust volume… it no longer just brings up the web player. They don’t even need to log in.
That’s weird. Can you share with me the link they are going to?
Making a few assumptions here is the probable fix:
a) hit “New Game” under the Hamburger Menu (the three horizontal lines at the top right-ish)
b) ONLY share the Share Audio link copied from that same menu with your players.
I presuuuuuuuuume your players are starting and stopping just the FREE content that anyone can run in the UI they are seeing? If they are getting access to a subscribers version of the content definitely let us know… maybe get one of them to send a screenshot of what they are seeing?
Mainly = thanks for reaching out and mostly THANKS for your support as a sub! 
Also, checking we are talking app.syrin… not… syrin…com/online/master/… right?