Hey @fefekrzr.
I remember that there were some issues around firewalld back during the bookworm upgrade. Did you check if you can see anything related to packets being dropped? I’ve seen you being part of the discussion then, so I assume you may have already checked this:
Aside from that, do you know if the issue occurs between browser and fbx or somewhere deeper down? If it’s on the browser side, you could try looking at the developer tools if there’s anything coming up. Alternatively, the standard question: Did you enable and check your logs?
Update / Another thought: Did anything change on the network around your setup, esp. around DNS?
Cheers & HTH,
Axel