The phone cannot make voice and video calls

### Steps to reproduce

I deployed the matrix synapse service and deployed coturn. I encountered a very strange thing;
1. When my phone makes a call or video call with another phone, it always shows that it is connecting and there is no response. My two phones use their own SIM card networks.

2. When my two phones are in the same network (usually wifi), they can talk normally.

3. When my phone calls with the computer, it also behaves normally. They are also in different networks.

I don’t understand why this is the case. I need to state that my coturn only provides ipv6 because my operator refuses to provide me with ipv4. The following is my coturn configuration：


This is my homeserver.yaml configuration file:


I tested my turn and it works fine.

### Outcome

I deployed the matrix synapse service and deployed coturn. I encountered a very strange thing;
1. When my phone makes a call or video call with another phone, it always shows that it is connecting and there is no response. My two phones use their own SIM card networks.

2. When my two phones are in the same network (usually wifi), they can talk normally.

3. When my phone calls with the computer, it also behaves normally. They are also in different networks.

I don’t understand why this is the case. I need to state that my coturn only provides ipv6 because my operator refuses to provide me with ipv4. The following is my coturn configuration：


This is my homeserver.yaml configuration file:


I tested my turn and it works fine.

### Your phone model

_No response_

### Operating system version

_No response_

### Application version and app store

_No response_

### Homeserver

_No response_

### Will you send logs?

Yes

### Are you willing to provide a PR?

Yes