I am using Samsung Galaxy Watch 4 and Network provider is Lyca.
I am able to register the eSim on my phone Nokia X30, but when I am trying to add a mobile plan for watch using samsung wearable app it errors out saying "EE-Lyca doesn't offer mobile plan for you watch"
Unfortunately the watch is not compatible with your service provider you will be unable to activate it however you can still use this watch connected to your phone and through Wi-Fi essentially it's the same as buying the Bluetooth version only
