Websocket connection is broken, which prevents confirmation when posting comments

When posting comments on salsa, I often never receive the confirmation and the submit button keeps spinning forever, waiting for a reply from the server. I found this the error in the console, which makes me think the response is sent from the server over this websocket that failed to open:

Firefox can’t establish a connection to the server at wss://salsa.debian.org/-/cable.

Here is the request from my browser for the websocket request:

GET /-/cable HTTP/1.1
Host: salsa.debian.org
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0
Accept: */*
Accept-Language: fr-FR,fr;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate, br, zstd
Sec-WebSocket-Version: 13
Origin: https://salsa.debian.org
Sec-WebSocket-Protocol: actioncable-v1-json, actioncable-unsupported
Sec-WebSocket-Extensions: permessage-deflate
Sec-WebSocket-Key: *********
DNT: 1
Connection: keep-alive, Upgrade
Cookie: logged_out_marketing_header_id=*******; hide_broadcast_message_token_expiration_banner=true; collapsed_gutter=true; super_sidebar_collapsed=false; sidebar_pinned_section_expanded=true; hide_no_ssh_message=false; preferred_language=en; event_filter=all; _gitlab_session=******
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: websocket
Sec-Fetch-Site: same-origin
Pragma: no-cache
Cache-Control: no-cache
Upgrade: websocket

And here is the response from the server:

HTTP/1.1 404 Not Found
Date: Sat, 28 Dec 2024 10:03:00 GMT
Server: Apache
X-Content-Type-Options: nosniff
X-Frame-Options: sameorigin
Referrer-Policy: no-referrer
X-Xss-Protection: 1
Permissions-Policy: interest-cohort=()
Strict-Transport-Security: max-age=15552000
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Content-Length: 1591
Content-Security-Policy: connect-src 'self' http://localhost:* ws://localhost:* wss://localhost:*; default-src 'self'; frame-ancestors 'self'; frame-src 'self' https://www.google.com/recaptcha/ https://www.recaptcha.net/ https://content.googleapis.com https://content-compute.googleapis.com https://content-cloudbilling.googleapis.com https://content-cloudresourcemanager.googleapis.com; img-src * data: blob:; object-src 'none'; script-src 'self' 'unsafe-eval' http://localhost:* https://www.google.com/recaptcha/ https://www.recaptcha.net/ https://www.gstatic.com/recaptcha/ https://apis.google.com 'nonce-xrSI/4ndDIRIoVwU52tJvA=='; style-src 'self' 'unsafe-inline'; worker-src 'self' blob:
Content-Type: text/html; charset=utf-8
Expires: Mon, 01 Jan 1990 00:00:00 GMT
Pragma: no-cache
X-Gitlab-Meta: {"correlation_id":"*****","version":"1"}
X-Request-Id: *******
X-Runtime: 0.012455
X-Clacks-Overhead: GNU Terry Pratchett
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive