Gathering ice candidates works but failing to connect

I have two different WebRTC clients: an Android device and an angular application. I set up a turn and stun server and both seems to work with the trickle ice tester and the webrtc tester.

As you can see here:

But all ice candidates fail in Firefox when I am watching the candidates in about:webrtc.

Does anyone have an explanation for this?
More info:

• A similar error occurs in Google Chrome, but the logs are from Firefox because Firefox has better logging.
• The devices are on different networks, so the host request should fail and the turn server is needed.
• The turn server is a coturn turn server, but I also tried it with a Pion turn server and the same result occurs.
• Firfox logs: https://gist.github.com/Nick-v-L/365b7da10039d28a6a23a27fea15df52
• Coturn logs: https://gist.github.com/Nick-v-L/04c3cfc677847e3cdcb7f6b5ca15c743

There was a simple error in my Android app. When receiving an ice candidate from the signaling server I did the following:

peerConnection.AddIceCandidate(new IceCandidate(sdpCandidate, sdpMLineIndex, sdpMid));

But as the documentation states you have to create an ice candidate in this order:

public IceCandidate(string sdpMid, int sdpMLineIndex, string sdp);

So I turned the sdpCandidate and sdpMid around to fix the issue.

peerConnection.AddIceCandidate(new IceCandidate(sdpMid, sdpMLineIndex, sdpCandidate));