MatrixRTC calling cannot be initiated from Element X Android (OxygenOS 15, OnePlus Nord CE4 Lite 5G) despite correct server focus; joining existing calls works

[DaSteff91]

Steps to reproduce

Steps to reproduce:

Start in Element X App

1. Logged into a self-hosted Synapse server at matrix.kite-engineer.de.

2. Create a new room (private). The room opens normally.

3. Tap the video camera icon in the top right. Element Call opens a video preview.

4. Tap "Join call". The app immediately displays the error:
   "Call not supported — Missing Matrix RTC focus for matrix.kite-engineer.de"

Additional observations I can reproduce consistently:

In some rooms (those created on another device), the error appears immediately when I tap the video camera icon, without showing the preview screen at all.

When I initiate a call from Element X on my phone, my LiveKit JWT authoriser receives no request at all (verified by watching its logs).

When I initiate the same call from Element Web on my desktop, I can join the call on my phone without any issues. In that case the LiveKit JWT service logs appear normally.

The .well-known/matrix/client file is correct and accessible directly from my phone’s browser.

The following log excerpts are from the Element X “Export logs” feature ("Report a problem" menu).

Errors when initiating a call:

2025-11-26T19:52:48.796375Z ERROR elementx: [ElementCall] :2 {"l..."MISSING_MATRIX_RTC_FOCUS","domain":"matrix.kite-engineer.de"} |
2025-11-26T19:53:27.211179Z ERROR elementx: [ElementCall] :2 {"l..."MISSING_MATRIX_RTC_FOCUS","domain":"matrix.kite-engineer.de"} |

WebView/Element Call embedded app errors:

2025-11-26T19:52:46.036873Z ERROR elementx: [ElementCall] ... has blocked origin. Have the server send the header with a valid value.
2025-11-26T19:53:27.178675Z ERROR elementx: [ElementCall] ... blocked origin. Have the server send the header with a valid value.

Logs that appear when joining a call initiated on Element Web:

[ElementCall] MatrixRTCSessionEvent.MembershipsChanged ...
[ElementCall] Disconnected from livekit room, state:disconnected |

Full logfile:

Attached in the report via app

Outcome

What did you expect?

I expected Element X Android to:

• Read the .well-known/matrix/client configuration from my homeserver.
• Detect the org.matrix.msc4143.rtc_foci configuration.
• Initiate a MatrixRTC call the same way Element Web does. thus allowing me to make (video) calls started via Element X.
• Contact my auth service (livekit-jwt) to create or join a LiveKit room.

What happened instead?

• No (video) call can be tarted. Element X Android reports:
  Call not supported — MISSING_MATRIX_RTC_FOCUS (domain: matrix.kite-engineer.de)
• No log entries showing up in the livekit-jwt container unlike when done via Element web/ ergo: no request to it is made from Element X

Your phone model

OnePlus Nord CE4 Lite 5G

Operating system version

OxygenOS 15.0

Application version and app store

Element X Version 25.11.2 (202511022)

Homeserver

matrix.kite-engineer.de

Will you send logs?

Yes

Are you willing to provide a PR?

No

[DaSteff91]

Related issues may be #4546 and #4528. Reinstallation, cleaning the cache, etc. didn´t do the job unfortunatelly

[eleimt]

@DaSteff91 Hi. Were you able to set up the calls? I'm having trouble with something, maybe you could give me some advice.

[DaSteff91]

Hey there @eleimt.

Via Element Web its possible for me to setup a call / video call, yes - but only there. Neither via Element X app on the phone nor via the Element Desktop version i can start the call.

Have you tried Element Web already?

[eleimt]

Hey there @eleimt.

Via Element Web its possible for me to setup a call / video call, yes - but only there. Neither via Element X app on the phone nor via the Element Desktop version i can start the call.

Have you tried Element Web already?

I tried, but it didn't work out so far.

[DaSteff91]

I could share my setup with you - if you want to: what way of communication do you prefere?

[eleimt]

I could share my setup with you - if you want to: what way of communication do you prefere?

Let's try Gmail scanit.74@gmail.com