Hi. I have the exact same issue with consuming StreamServices on mobile devices.
We are using GeoeventServer to stream our own data from our own geoevent server. Works fine on every device except Mobile phones and ipads (have not tried android pads).
I have no issue browsing to the ArcGIS Server rest interface from the phone, and opening the service on my phone using the View in: ArcGIS JavaScript.
But by opening it that way on the mobile device(rest api), the stream service url: is not changing from red to green, like it does on a computer, so the stream is a no go that way also.
I am using the service in a webapp, using arcgis online WebappBuilder.
The same app works fine on everything except mobile devices. And i have tried using 4G 5G and Wifi, with the same result.
I have also made the url public, in order to rule out it being unable to reach due to credentials.