Link new device by QR code is not working

[Artiom-M]

Description

I have enabled login_via_existing_session and even installed matrix_http_rendezvous_synapse.SynapseRendezvousModule but still see

QR code not supported
Your account provider doesn't support signing into a new device with a QR code.

Steps to reproduce

On Synapse desktop

• click on avatar -> Link new device
• shows Settings: Sessions configuration screen with : QR code not supported
  Your account provider doesn't support signing into a new device with a QR code.

Homeserver

Personal home server

Synapse Version

{"versions":["r0.0.1","r0.1.0","r0.2.0","r0.3.0","r0.4.0","r0.5.0","r0.6.0","r0.6.1","v1.1","v1.2","v1.3","v1.4","v1.5","v1.6","v1.7","v1.8","v1.9","v1.10","v1.11"],"unstable_features":{"org.matrix.label_based_filtering":true,"org.matrix.e2e_cross_signing":true,"org.matrix.msc2432":true,"uk.half-shot.msc2666.query_mutual_rooms":true,"io.element.e2ee_forced.public":false,"io.element.e2ee_forced.private":false,"io.element.e2ee_forced.trusted_private":false,"org.matrix.msc3026.busy_presence":false,"org.matrix.msc2285.stable":true,"org.matrix.msc3827.stable":true,"org.matrix.msc3440.stable":true,"org.matrix.msc3771":true,"org.matrix.msc3773":false,"fi.mau.msc2815":false,"fi.mau.msc2659.stable":true,"org.matrix.msc3882":true,"org.matrix.msc3881":false,"org.matrix.msc3874":false,"org.matrix.msc3912":false,"org.matrix.msc3981":true,"org.matrix.msc3391":false,"org.matrix.msc4069":false,"org.matrix.msc4028":false,"org.matrix.msc4108":false,"org.matrix.msc4140":false,"org.matrix.msc4151":false,"org.matrix.simplified_msc3575":true}}

Installation Method

pip (from PyPI)

Database

postgres

Workers

Single process

Platform

Oracle enterprise Linux 8 (VPS)

Configuration

Options I have configured for link new device:

modules:
  - module: matrix_http_rendezvous_synapse.SynapseRendezvousModule
    config:
      prefix: /_synapse/client/org.matrix.msc3886/rendezvouz
experimental_features:
  msc3886_enabled: true
  msc3886_endpoint: /_synapse/client/org.matrix.msc3886/rendezvous

login_via_existing_session:
    enabled: true
    require_ui_auth: false
    token_timeout: "5m"

Relevant log output

I don't see anything special in the log when selecting the QR page...


Dec 11 11:19:22 server synapse[403003]: root: [main] ***** STARTING SERVER *****
Dec 11 11:19:22 server synapse[403003]: root: [main] Server /home/matrix/synapse/venv/lib64/python3.11/site-packages/synapse/app/homeserver.py version 1.120.2
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,241 - root - 353 - WARNING - main - Server /home/matrix/synapse/venv/lib64/python3.11/site-packages/synapse/app/homeserver.py version 1.120.2
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,241 - root - 358 - WARNING - main - Copyright (c) 2023 New Vector, Inc
Dec 11 11:19:22 server synapse[403003]: root: [main] Copyright (c) 2023 New Vector, Inc
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,241 - root - 359 - WARNING - main - Licensed under the AGPL 3.0 license. Website: https://github.com/element-hq/synapse
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,242 - root - 362 - INFO - main - Server hostname: xxx
Dec 11 11:19:22 server synapse[403003]: root: [main] Licensed under the AGPL 3.0 license. Website: https://github.com/element-hq/synapse
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,242 - root - 363 - INFO - main - Instance name: master
Dec 11 11:19:22 server synapse[403003]: root: [main] Server hostname: vega-forum.club
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,242 - root - 364 - INFO - main - Twisted reactor: AsyncioSelectorReactor
Dec 11 11:19:22 server synapse[403003]: root: [main] Instance name: master
Dec 11 11:19:22 server synapse[403003]: root: [main] Twisted reactor: AsyncioSelectorReactor
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,721 - twisted - 279 - INFO - main - Redirected stdout/stderr to logs
Dec 11 11:19:22 server synapse[403003]: twisted: [main] Redirected stdout/stderr to logs
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,745 - matrix_http_rendezvous_synapse - 65 - INFO - sentinel - Mounting rendez-vous server on /_synapse/client/org.matrix.msc3886/rendezvouz, w>
Dec 11 11:19:22 server synapse[403003]: matrix_http_rendezvous_synapse: [sentinel] Mounting rendez-vous server on /_synapse/client/org.matrix.msc3886/rendezvouz, with a TTL of 1m and max payload size of 4.0 kiB
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,764 - twisted - 279 - INFO - sentinel - SynapseSite starting on 18448
Dec 11 11:19:22 server synapse[403003]: twisted: [sentinel] SynapseSite starting on 18448
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,765 - twisted - 279 - INFO - sentinel - SynapseSite starting on 18448
Dec 11 11:19:22 server synapse[403003]: twisted: [sentinel] SynapseSite starting on 18448
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,782 - twisted - 279 - INFO - sentinel - SynapseSite starting on 8008
Dec 11 11:19:22 server synapse[403003]: twisted: [sentinel] SynapseSite starting on 8008
Dec 11 11:19:22 server matrix-synapse[403003]: 2024-12-11 11:19:22,783 - twisted - 279 - INFO - sentinel - SynapseSite starting on 8008
Dec 11 11:19:22 server synapse[403003]: twisted: [sentinel] SynapseSite starting on 8008
Dec 11 11:19:22 server systemd[1]: Started Synapse Matrix homeserver.

### Anything else that would be useful to know?

_No response_

[YamatoRyou]

The related functions you adopted are outdated and have been abandoned.
Currently QR code login only supports the next generation Element client, and Synapse needs to configure an external service: https://github.com/element-hq/matrix-authentication-service

[Artiom-M]

I still have few questions:

1. I haven't found anything about adding a device with QR code in the matrix-authentication-service document.
2. I have the latest desktop Element (1.11.87), what is the next generation client that is supporting QR code device addition?
3. How to use login_via_existing_session ? I have not found any user side documentation, is there a client that has implemented it?
   Thank you.

[YamatoRyou]

I still have few questions:

1. I haven't found anything about adding a device with QR code in the matrix-authentication-service document.
2. I have the latest desktop Element (1.11.87), what is the next generation client that is supporting QR code device addition?
3. How to use login_via_existing_session ? I have not found any user side documentation, is there a client that has implemented it?
   Thank you.

Answer respectively:

1. The service's documentation does not mention QR code login, but the Element desktop (web) client does require it in order to be usable (based on my experience).
2. Element desktop (web) client displays the QR code, and Element X (Andorid & iOS) scans the QR code displayed by the former.
3. login_via_existing_session has no meaning in this case and can be deleted.

https://github.com/element-hq/element-x-ios
https://github.com/element-hq/element-x-android

[warioishere]

seriously? I need to add another external service for element with a own domain for this to work properly that needs another Server? It was simple and easy before with matrix_http_rendezvouz. How many things do i need to add to make things work like it did some time ago. Also now an Element-Call Server for this simple thing to call, no more voip support on element-x, now I have to install another OpenID connect Provider for this to work?

Why the fucking helll is matrix/element trying to invent things new if there are thinks like keycloak and authentik already there? I connected my instance already with keycloak, now I need another provider in place.

I fucking cannot believed how this so much loved matrix project is beeing destroyed

[Artiom-M]

When I started my matrix servers many years ago it was simple and worked better than XMPP. Now it seems to take a turn that will scare away small instance holders like me...

[warioishere]

thats what I am so sad about too
You need a shitload off external applications now for these things, which before worked before with a simple and short yaml file or another pip module.
Worst thing for me is that they drop p2p calling and introducing this horrible matrix-call bullshit. Sorry but I have no other words for that.
I want a simple and easy calling service. I donated a lot and I just see turning matrix into a unmanagable thing that no normal admin can use anymore.

Before calling was possible in simple p2p style with a turnserver to manage NAT problems, thats all
Now a matrix-call server for a horrible calling functionality, and it needs a domain
Another Authentication service which also needs a domain.
and the best thing is, nothing works anymore!
Great development

[Artiom-M]

Thankfully there is Signal or Threema... I will end up moving there. I really love decentralisation idea, but Matrix team may not leave me any choice. Unless a project like Conduit will just continue to follow original matrix specs, with a client like FluffyChat..