Binobuchy that's the stacktrace, which only shows where the error happened, but doesn't really help when identifying why it happened. If you scroll a couple of lines above, there should be the main error message. Line that starts with #<number>
is a stacktrace
NianwenDan Could you add error code when something wrong?
I personally can't do that because I do not maintain Flarum, I am just a member of the community. I make assumptions of what could be wrong based on my knowledge with Flarum. But you can suggest this to devs either via this forum or GitHub.
IMO error codes to frontend will probably not be added - there's already browser console and server-side logs that contain more detailed information. I think that it is up to users how much details they provide that will help the community to find out what's wrong, and also error codes wouldn't probably be enough either