On screen calls notifications showing only when the two devices are on the same wifi !!

### Steps to reproduce

This our sygnal config

```
apps:

lu.bundle.id:
type: apns
keyfile: /etc/sygnal/AuthKey_F4M5NC9S98.p8
key_id: F4M5N
team_id: 48R4V
topic: lu.bundle.id
push_type: alert
platform: sandbox

lu.bundle.id.voip:
type: apns
certfile: /etc/sygnal/voipem.pem
topic: lu.bundle.id
push_type: voip
platform: sandbox
```

As mentioned in the title, the mobile shows on screen call notification only when the other device is on the same wifi.

Please not is not turn/stun issue. because the calls are working fine. I am talking only about the on screen notification.

Regards,

### Outcome

The ios app should show an screen with someone calling, and the user should be able to accept the call.

### Your phone model

_No response_

### Operating system version

_No response_

### Application version

_No response_

### Homeserver

_No response_

### Will you send logs?

No