Video call works in WIFI connection, but not with Cellular connection

[farnyu]

Please provide us with the following information:

I ran the AddVideo Quickstart. I have one iPhone X iOS 15 calling another iPhone 8 iOS 15. Video call works when both phones are connected to WIFI. Impressive.

But, when I DISCONNECT iPhone X from WIFI, and only use cellular, the Audio call establish, but when I turn on Video, call will end immediately.

As soon as I reconnect iPhone X to WIFI, Video call function again.

This issue is for a: (mark with an x)

- [X] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)

Minimal steps to reproduce

1. From Azure Communication Service portal, generate two sets of User Access Tokens.

2. Populate 1st set of User Access Token in Add Video Call Project
3. Build it on an iPhone
4. Populate 2nd User Access Token in Add Video Call Project
5. Build it on another iPhone
6. User 1 of the iPhone to call the other iPhone by entering who to call with "Identity" you obtained from User Access Tokens page from step 1.
7. Make the Call when bot iPhones are connected to WIFI. Video call should establish.
8. Disconnect one of the phones from WIFI, and only use Cellular phone (make sure it has a sim card, and with mobile data connection)
9. Make the call again, you should observer video call cannot be established.
10. To make sure, reconnect the WIFI connection on both phones, and Video call can be established again.

Any log messages given by the failure

Expected/desired behavior

Video call should work regardless WIFI or Cellular connection

OS and Version?

macOS Big Sur v1.16, Xcode 13.

Versions

Mention any other details that might be useful

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