WebRTC offer is missing lots of fields

I have a web app that plays video broadcasted using WebRTC. I'm using a COTURN simple implementation (as described here: https://gabrieltanner.org/blog/turn-server). My turnserver.conf looks like this:

# TURN server name and realm
realm=<server_domain>
server-name=turnserver

# Use fingerprint in TURN message
fingerprint

# IPs the TURN server listens to
listening-ip=0.0.0.0

# External IP-Address of the TURN server
external-ip=<server_public_ip>

# Main listening port
listening-port=3478

# Further ports that are open for communication
min-port=10000
max-port=20000

# Log file path
log-file=/var/log/turnserver.log

# Enable verbose logging
verbose

# Specify the user for the TURN authentification
user=username:password

# Enable long-term credential mechanism
lt-cred-mech

# SSL certificates
cert=<crt_file>
pkey=<key_file>

# 443 for TURN over TLS, which can bypass firewalls
tls-listening-port=443

And I tested this server here: https://webrtc.github.io/samples/src/content/peerconnection/trickle-ice/ and it works fine.

On my WebApp I'm doing

  const test = () => {
    const configuration = {
      iceServers: [
        { urls: "stun:stun.l.google.com:19302" },
        {
          urls: "turn:<domain>:3478",
          username: "username",
          credential: "password",
        },
      ],
    };
    let pc = new RTCPeerConnection(configuration);
    pc.ontrack = function (event) {...}
    pc.createOffer()
      .then((offer) => { 
         console.log(offer);
      }

But the offer looks like this:

    RTCSessionDescription {type: "offer", sdp: "v=0
    ↵o=- 35287960452273588 2 IN IP4 127.0.0.1
    ↵s=-…0 0
    ↵a=extmap-allow-mixed
    ↵a=msid-semantic: WMS
    ↵"

which causes the other peer to throw SetRemoteDescription called with no fingerprint

and I'm not sure why is it missing so much information, am I doing something wrong?

Thank you in advance!

When offering you need to have at least one media section. You can either add a Transceiver or do a data channel.

let pc = new RTCPeerConnection()

// Create data channel
pc.createDataChannel('foobar')

// Create a audio or video transceiver
pc.addTransceiver('audio')
pc.addTransceiver('video')