Obtuse error message appears if the server fails to respond to a delete device request

[anoadragon453]

Steps to reproduce

• Enable the "New session manager" in Labs
• Go to the "Sessions" tab in Settings
• Select a device or two and click "Sign out"
• Have a homeserver which will not answer this request in time, and thus the reverse proxy returns a 504 (you can simulate with a reverse proxy that always returns a 504 for /_matrix/client/r0/delete_devices requests.
• Receive the above error message, which is very confusing for a user.

Outcome

What did you expect?

A 504 means the homeserver did not respond to the request quickly enough so the reverse proxy has timed the request out. The devices are eventually deleted server-side, but in a minute or two. A more helpful error message would be something along the lines of "The homeserver is taking a while to complete this request. Wait a few minutes and try again."

What happened instead?

I received this cryptic error with no recommended user action, leading to potential frustration.

Operating system

NixOS

Application version

Element version: 1.11.17, Olm version: 3.2.12

How did you install the app?

No response

Homeserver

No response

Will you send logs?

No