10.9-Unstable, Unstable Plugin Repository not working

[pixel24]

Hello everyone,
Following the documentation, I removed the Stable Plugin Repository and added the Plugin-Unstable repository, then restarted the server.
Subsequently, I cleared the browser cache and logged in as an admin again. The catalog is completely empty. In the log file, I find:

Code:

Mär 27 17:37:20 media02 jellyfin[848]: System.Net.Http.HttpRequestException: Response status code does not indicate success: 500 (Proxy Failure).
Mär 27 17:37:20 media02 jellyfin[848]:    at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
Mär 27 17:37:20 media02 jellyfin[848]:    at System.Net.Http.Json.HttpClientJsonExtensions.<FromJsonAsyncCore>g__Core|12_0[TValue,TJsonOptions](HttpClient client, Task`1 responseTask, Boolean usingResponseHeadersRead, CancellationTokenSource linkedCTS, Func`4 deserializeMethod, TJsonOptions jsonOptions, CancellationToken cancellationToken)
Mär 27 17:37:20 media02 jellyfin[848]:    at Emby.Server.Implementations.Updates.InstallationManager.GetPackages(String manifestName, String manifest, Boolean filterIncompatible, CancellationToken cancellationToken)
Mär 27 17:37:29 media02 jellyfin[848]: [17:37:29] [INF] WS 192.168.83.141 request
Mär 27 17:37:48 media02 jellyfin[848]: [17:37:48] [ERR] An error occurred while accessing the plugin manifest: https://repo.jellyfin.org/files/plugin-unstable/manifest.json
Mär 27 17:37:48 media02 jellyfin[848]: System.Net.Http.HttpRequestException: Response status code does not indicate success: 500 (Proxy Failure).
Mär 27 17:37:48 media02 jellyfin[848]:    at System.Net.Http.HttpResponseMessage.EnsureSuccessStatusCode()
Mär 27 17:37:48 media02 jellyfin[848]:    at System.Net.Http.Json.HttpClientJsonExtensions.<FromJsonAsyncCore>g__Core|12_0[TValue,TJsonOptions](HttpClient client, Task`1 responseTask, Boolean usingResponseHeadersRead, CancellationTokenSource linkedCTS, Func`4 deserializeMethod, TJsonOptions jsonOptions, CancellationToken cancellationToken)
...

++ Test Environment ++

+ Server +
OS: Debian 15.5 / latest patch level
Jellyfin 10.9 / Build 2024032505
NGINX: 1.22.1-9 / Configured according to Jellyfin documentation

+ Client +
Linux Mint 21.3 Virgini / Firefox 124.0.1
Official Android Client 2.6.0

[crobibero]

Are you able to open the manifest url directly in your browser?

[pixel24]

Yes, I initially tested that, and it worked. Then, I removed the repo again, restarted the VM with Jellyfin, and also cleared the browser cache. After that, the catalog was displayed, and the error in the log was gone.

Before any significant action in JF-Unstable, I take a snapshot of the VM. I reverted to this snapshot and repeated the entire process. However, the error could not be reproduced.

I suspect this might be a specific/one-time issue with my Firefox.