Why Does D-ID WebRTC Streaming API (Free Trial) Return a Muted/Black Video Track on Mobile While Audio Plays Correctly?

Hello D-ID Support,

I am using your /talks/streams WebRTC streaming API with a free trial API key in my React Native mobile app (using react-native-webrtc). The ICE connection is established, and I receive both audio and video tracks. The video track appears with readyState: "live" but is muted and no video frames are rendered (the screen is black), while audio plays correctly.

On the web, using your pre-rendered /talks API, video playback works perfectly.
Is there a limitation with the free trial API for streaming video to mobile, or are there known codec/hardware restrictions?
Is there anything specific I should check or configure to get video frames working on mobile?

Thank you for your help!