On the product archive page, the filters are very slow. When you select the in-stock filter it takes 2 minutes to load the result since we published the site. Before it was ok.
Could it be our security plugin (Defender PRO) delaying the result?
Yes – any firewall or security plugins can affect the performance, if they do a heuristics check of some sort. If it was working before, it must be a 3rd party software causing the problem.
I recommend trying different settings on the security plugins, checking the server firewall – and also disabling all of them temporarily to see if it changes anything.