Guest Mode
Beginning with the 2.1.0 app / 3.31 firmware, ZWO introduced the concept of a "master" controller, and "guest" connections that can observe, but not control the device.
SSC must be the master in order to control the SeeStar S50.
If launched first, it will claim control.
If the SeeStar app is launched first, SSC will enter Guest mode, and most functions will be restricted.
To get the SeeStar app to release control, go to:
Advanced Settings -> Demonstration Mode
If Guest mode is enabled, press the small info icon (i) next to the text - then press the "Release control" button
SSC will claim control if launched first if no client has grabbed control.
To explicitly claim, or release control - this can be done in the SSC's command page, under Startup/Shutdown commands.
Note that you must release control from whatever client has it before you can claim control from SSC.
You can now disable guest mode. Doing so will make your life easier, unless you're worried about other people trying to grab control of your scope.
Whether ALP has control, and the connected clients can be seen on this page
As of v2.3.4, SSC has a "Guest Mode" page, to indicate what clients are connected to the scope, and who has control.
An example video is below, showing ALP running on a Mac, a Raspberry Pi, and the SeeStar app on an iPhone. Control is released, then gained again