Hello, the problem started with detectportal opening a page http://detectportal.firefox.com/canonical.html even though I am connected to my regular private WLAN and my connection is fine (e.g. email works). I get a very weird-looking page - see uploaded image - where "value-domain.com" is mentioned I then disabled detectportal. Now the browser loads pages again, but on two pages I got an HSTS alert - see image. When I open the box it says the certificate is not valid for this website, the error code is SSL_ERROR_BAD_CERT_DOMAIN. Looking at the certificate I see it is registered to said "value-domain.com". One of the websites that returned the alert was duckduckgo and the other one is the website of my ISP and they usually both load just fine. Any other webpages seem to load normally, I guess the reason these two do not has to do with the fact that they are the only ones I tried to load while detectportal displayed the network login alert. So I guess that somehow then this false certificate was associated with both duckduckgo and my ISP during that time. I hope there is some way I can reset that, and I also hope there is some fix that does not show the login page when I reactivate detectportal. Thank you very much for your time. Regards, Lukas