Authenticated media requests don't seem to work at all?

<!-- All bug reports must provide the following background information Text between <!-- and --​> marks will be invisible in the report. IF YOUR ISSUE IS CONSIDERED A SECURITY VULNERABILITY THEN PLEASE STOP AND DO NOT POST IT AS A GITHUB ISSUE! Please report the issue responsibly by disclosing in private by email to security@matrix.org instead. For more details, please see: https://www.matrix.org/security-disclosure-policy/ --> ### Background information <!-- Please include versions of all software when known e.g database versions, docker versions, client versions --> - **Dendrite version or git SHA**: 0.13.7 - **SQLite3 or Postgres?**: Postgres - **Running in Docker?**: No - **`go version`**: Irrelevant/unknown (using as packaged from Nixpkgs) - **Client used (if applicable)**: Cinny/Element ### Description - **What** is the problem: Media requests to servers that only support authenticated media requests (like matrix.org itself) always 404 - **Who** is affected: Everyone using Dendrite - **How** is this bug manifesting: Log messages about failed media requests - **When** did this first appear: Recently, likely when matrix.org disabled unauthenticated fetch <!-- Examples of good descriptions: - What: "I cannot log in, getting HTTP 500 responses" - Who: "Clients on my server" - How: "Errors in the logs saying 500 internal server error" - When: "After upgrading to 0.3.0" - What: "Dendrite ran out of memory" - Who: "Server admin" - How: "Lots of logs about device change updates" - When: "After my server joined Matrix HQ" Examples of bad descriptions: - What: "Can't send messages" - This is bad because it isn't specfic enough. Which endpoint isn't working and what is the response code? Does the message send but encryption fail? - Who: "Me" - Who are you? Running the server or a user on a Dendrite server? - How: "Can't send messages" - Same as "What". - When: "1 day ago" - It's impossible to know what changed 1 day ago without further input. --> ### Steps to reproduce <!-- Please try reproducing this bug before submitting it. Issues which cannot be reproduced risk being closed. --> - Start an encrypted DM with someone from Matrix.org - Have them send an image - Observe error <!-- Describe how what happens differs from what you expected. If you can identify any relevant log snippets from server logs, please include those (please be careful to remove any personal or private data). Please surround them with ``` (three backticks, on a line on their own), so that they are formatted legibly. Alternatively, please send logs to @kegan:matrix.org, @s7evink:matrix.org or @devonh:one.ems.host with a link to the respective Github issue, thanks! --> ```log Sep 10 18:08:41 homura dendrite[14339]: time="2024-09-11T00:08:41.576265018Z" level=error msg="r.fetchRemoteFileAndStoreMetadata: failed to fetch remote file" MediaID=redacted Origin=matrix.org error="File with media ID \"redacted\" does not exist on matrix.org" req.id=KiQCE521bkpb req.method=GET req.path=/_matrix/media/v3/download/matrix.org/redacted ``` all redacteds are the same ID.