HAproxy on PFsense (websocket working) Updated Dec24

[gaming09]

This is an excellent help - I had no idea getting Jellyfin to work behind a roxy would be so complicated!
However, I have checked and rechecked this guide and my settings three times now and keep getting this error...

Errors found while starting haproxy
[NOTICE] (98607) : haproxy version is 2.9.14-7c591d5
[NOTICE] (98607) : path to executable is /usr/local/sbin/haproxy
[ALERT] (98607) : config : parsing [/var/etc/haproxy_test/haproxy.cfg:77] : error detected in frontend 'https_shared-merged' while parsing 'http-after-response set-header' rule : sample fetch <req.hdr(Upgrade)]> may not be reliably used here because it needs 'HTTP request headers' which is not available here.
[ALERT] (98607) : config : Error(s) found in configuration file : /var/etc/haproxy_test/haproxy.cfg

I set up following Lawrence's guide and thus far did get immich to work through the proxy, though that was the only one so far....

Would anyone have any suggestions please. Running on PfSense CE 2.8.0 RELEASE.

Thanks in anticipation!

try this instead HAProxy > Frontends > Edit the relevant frontend > Advanced settings > Frontend pass thru field.
http-request set-var txn.upgrade req.hdr(Upgrade)
http-after-response set-header Upgrade %[var(txn.upgrade)]