SSE causes Apache to hang
I've set up a new hub, basically the same as netzgemeinde.eu , worked flawlessly at first. However, after a couple of clicks the connection somehow stalled - the browser was busy, an empty page came up basically forever. This was hard to debug, because there was next to none infos in the log file (php or apache) which could point out the problem, I tried downgrading apache, switching between php 7.4 and 8.0 (both FPM, of course), switching between Redis and files for session, I even temporarily installed tideways - but tideways didn't find anything at all, in fact tideways didn't get any data after the stalling. Only restarting either apache or php-fpm make the site work again.
I finally found the problem: SSE. After disabling SSE via admin panel the site worked flawlessly.
What's also vexing: netzgemeinde.eu had also SSE enabled (now disabled) and hasn't encountered such problems - this was really hard to debug.
