Remote Stream Issue on IOS

I am using WebRTC with a TURN server. Everything works fine on the local network when using STUN. However, when I make a call from a different network, I encounter a strange issue.

Current Issue:

  • When I make a call from iPhone 15 to iPhone 11 on different networks, it works perfectly.
  • However, when I make a call from iPhone 11 to iPhone 15, I get only a black screen on the iPhone 15.

I am unsure about the cause of this behavior, as the reverse works as expected. Any help would be appreciated.