Online / 6 & 7 February 2021


Troubleshooting Matrix at FOSDEM 2021

Troubleshooting Matrix at FOSDEM 2021

This year, FOSDEM will use Matrix to host the Q&A sessions after each talk, and chat rooms.

Matrix is a federated decentralised chat protocol. It combines some of the more desirable features of IRC, Slack, and Signal.

Without using Matrix, you can still do the following:

Quick Start

Whilst there are many ways to participate in the FOSDEM 2021 Matrix rooms, the most straight-forward should be: isn't working in my browser!

Some privacy-oriented browser extensions (such as EFF Privacy Badger may block Element from contacting the FOSDEM Matrix home servers. That's because Element operates as a full autonomous Matrix protocol client (independent of the URL where its code is hosted).


Things are mostly working, but the video stream isn't quite right...

No audio? There's an 'unmute' button to the right of the stream (when it's not in full-screen mode). Still not working? See below.

Jitsi occasionally has problems with Firefox - this is related to the WebRTC standardisation, which is still work in progress, and part to the implementation in Firefox. Try using:

Still no luck? Go to

I "unpinned" the video and now it's gone!

If you click on the info icon (small i) in the top right corner, you see a list of widgets and you can pin them again.

I'd prefer to just use my existing Matrix client and/or home server (self-hosted or otherwise)

You can do that of course, but if you are self-hosting Element, then you should update to at least v1.7.20.

The FOSDEM Matrix home server name is (NOT

Other Matrix clients may be missing features which are necessary for some FOSDEM functionality.

Your latency may be higher if you are accessing the rooms via another home server.

Third-party Matrix home servers may block access the Matrix rooms (either deliberately, or because of misconfiguration).

If you're still having problems, please try Quick Start, to work out if the issue that you're seeing is due to the homeserver version, or Matrix client. If you wish, you can use the Element instance at to access other home servers if you wish (click the "sign-in" button, and then change the specified home server using the Edit link).


If you are still having trouble, you can get to the FOSDEM InfoDesk via IRC at the #fosdem-infodesk channel on the Libera.Chat IRC network.

Participating via IRC

Most FOSDEM 2021 Matrix rooms are "bridged" to channels on the Libera.Chat IRC network. e.g. the Matrix room is bridged to the Libera.Chat IRC channel #fosdem-infodesk. Other Matrix rooms follow the same pattern. The keynotes stream is currently on IRC as #fosdem-fosdem.