@lakwnikos @knuthollund Another thought:
3) Could this be a denial-of-service attack against quitter.se and quitter.no?? Or some misconfigured other instance flooding q.no and q.se??

Because: Some 3 weeks ago I told @knuthollund on #IRC about the issue and he said he would have a look. Soon after that the problem was completely gone and quitter.no worked flawlessly for at least the rest of the day! And moreover: quitter.se also worked flawlessly! But later it turned out @knuthollund didn't actually do anything at that point, not even restart anything.)

So I think that something on the fediverse network must have changed within those couple of hours. I think the cause of the problem is somewhere in the internet and that cause did stop its weird behaviour against quitter.se and quitter.no just for a while. Too bad the problem came back the next day.

I think one could check the logs of the webserver or use wireshark to look out for weird/excessive traffic.
!gnusocial