Cannot rejoin left room: "No known servers"

[Bubu]

Steps to reproduce

1. When I leave a room (or get kicked by the IRC bridge...)
2. and I happen to be the last user on my server that was in that room
3. and I want to re-join and click the re-join button the room preview screen

Outcome

What did you expect?

My server re-joins the room over federation

What happened instead?

Without fail I get the "No known servers" error popup. I just confirmed with devtools that element-desktop is trying to join by roomid without server_name parameters

Operating system

ArchLinux

Application version

Element version: 1.10.15 Olm version: 3.2.8

How did you install the app?

pacman -S element-desktop

Homeserver

v1.61.1

Will you send logs?

No

[bwindels]

This issue seems to be specifically about Element not sending server_name in the join request.

[rda0]

The same happens for /join !room_id@server command which results in:
MatrixError: [404] No known servers (https://server.x/_matrix/client/r0/join/!zzzzzzzzzzz%3Aserver.y)
Server log: "POST /_matrix/client/r0/join/!zzzzzzzzzzz%3Aserver.y HTTP/2.0" 404

[aaronraimist]

@rda0 that's not a bug. A room ID alone cannot reliably be used to join a room.

Humans should use Room Addresses (Aliases) whenever possible.

[Bubu]

When you are the last user in room and try to left client says to you that you can not join in the future.
No bug here.

This issue is about public rooms. I don't think you get this warning message for them. And you should definitely be able to rejoin them. So, yes, this is indeed a bug.

[aaronraimist]

To be clear that issue (matrix-org/matrix-spec#95) would happen if you are the very last user in the room. Not the last user on your server.

Element does provide a warning in all rooms, public or not, when you attempt to leave as last user in the room.