Failed to send_join via any server when joining #rust:matrix.org.

[cyphar]

Description

I've been running my own homeserver for over a year now, and it works great. But I just tried to join #rust:matrix.org and synapse fails to join with the following error shown on the client:

Failed to send_join via any server

The full backtrace for one of these events is attached. Looks like the core issue is this AttributeError:

Traceback (most recent call last):
  File "/usr/lib/python3.7/site-packages/synapse/federation/federation_client.py", line 402, in _try_destination_list
    res = await callback(destination)
  File "/usr/lib/python3.7/site-packages/synapse/federation/federation_client.py", line 589, in send_request
    valid_pdus_map = {p.event_id: p for p in valid_pdus}
  File "/usr/lib/python3.7/site-packages/synapse/federation/federation_client.py", line 589, in <dictcomp>
    valid_pdus_map = {p.event_id: p for p in valid_pdus}
AttributeError: 'coroutine' object has no attribute 'event_id'

Steps to reproduce

• Run matrix-synapse 1.11.0.
• Try to join #rust:matrix.org.
• Note the behaviour listed above.

Version information

• Homeserver: cyphar.com
• Version: 1.11.0.
• Install method: Package manager.
• Platform: openSUSE Tumbleweed, inside an LXD container on openSUSE Leap 15.1.

[clokep]

Thanks for the report! This looks like it is a duplicate of #6978, which was fixed in Synapse 1.11.1. Please re-open this issue if it is still happening after upgrading Synapse to 1.11.1.

[cyphar]

Ah, thanks. Yeah, we're working on updating the package in openSUSE at the moment. ❤️

[sl5net]

i have the problem problem from window to linux mint. in the LAN.
"Failed to make_join via any server".

Element version: 1.7.1
olm version: 3.1.3
Homeserver is https://matrix.netzgemeinde.eu
Identity Server is https://vector.im

[sl5net]

please set "Closed" too "open"

[cyphar]

That's odd, it seems like your homeserver is actually running 1.17.0 where the issue should've been fixed:

% curl https://matrix.netzgemeinde.eu/_matrix/federation/v1/version 
{
    "server": {
        "name": "Synapse",
        "version": "1.17.0"
    }
}

[mnowiasz]

Tried to join #rust myself, got the following error in homeserver.log:

2020-07-20 07:56:53,478 - synapse.http.server - 79 - ERROR - GET-2503855 - Failed handle request via 'ClientDirectoryServer': <XForwardedForRequest at 0x7f43a75d5370 method='GET' uri='/_matrix/client/r0/directory/room/%23rust%3Amatrix.org' clientproto='HTTP/1.1' site=8008>
Traceback (most recent call last):
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/http/matrixfederationclient.py", line 436, in _send_request
    response = yield request_deferred
twisted.web._newclient.ResponseNeverReceived: [<twisted.python.failure.Failure twisted.internet.defer.CancelledError: >]

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/http/server.py", line 228, in _async_render_wrapper
    callback_return = await self._async_render(request)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/http/server.py", line 399, in _async_render
    callback_return = await raw_callback_return
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/rest/client/v1/directory.py", line 52, in on_GET
    res = await dir_handler.get_association(room_alias)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/handlers/directory.py", line 236, in get_association
    result = await self.federation.make_query(
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/internet/defer.py", line 1416, in _inlineCallbacks
    result = result.throwExceptionIntoGenerator(g)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
    return g.throw(self.type, self.value, self.tb)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/federation/transport/client.py", line 176, in make_query
    content = yield self.client.get_json(
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/internet/defer.py", line 1416, in _inlineCallbacks
    result = result.throwExceptionIntoGenerator(g)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
    return g.throw(self.type, self.value, self.tb)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/http/matrixfederationclient.py", line 794, in get_json
    response = yield self._send_request_with_optional_trailing_slash(
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/internet/defer.py", line 1416, in _inlineCallbacks
    result = result.throwExceptionIntoGenerator(g)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
    return g.throw(self.type, self.value, self.tb)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/http/matrixfederationclient.py", line 252, in _send_request_with_optional_trailing_slash
    response = yield self._send_request(request, **send_request_args)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/internet/defer.py", line 1416, in _inlineCallbacks
    result = result.throwExceptionIntoGenerator(g)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/twisted/python/failure.py", line 512, in throwExceptionIntoGenerator
    return g.throw(self.type, self.value, self.tb)
  File "/home/matrix/synapse/env/lib/python3.8/site-packages/synapse/http/matrixfederationclient.py", line 443, in _send_request
    raise RequestSendFailed(e, can_retry=True) from e
synapse.api.errors.RequestSendFailed: Failed to send request: ResponseNeverReceived: [<twisted.python.failure.Failure twisted.internet.defer.CancelledError: >]````

[clokep]

That seems to be unrelated to this issue (the stack trace is different). My initial guess would be that the server was not responding / was slow to respond.

[Half-Shot]

#rust:matrix.org contains ~6800 members. This is likely caused by #1211.