Andy and I aren't able to make a call connect, regardless of which direction we're dialing.

### Steps to reproduce

1. Where are you starting? What can you see?
In a DM, initiating a call

2. What do you click?
Video call

3. More steps…

### Outcome

#### What did you expect?

#### What happened instead?
The video call frame popped up for a second, then disappeared.
When the call did eventually connect (after four or so goes), Andy couldn't hear me.

### Operating system

Widnows

### Application version

Element Nightly version: 0.0.1-nightly.2021110801 Olm version: 3.2.3

### How did you install the app?

website

### Homeserver

me on lant.uk, andy on matrix.org

### Will you send logs?

Yes