behilms I've had the same problem a couple of times though I have found ways to fix it. It's caused by malware or maybe expired cookies and cache, so be sure to clear your browser data. Simply, don't use your PC and restart your router, I normally turn the data on my phone off and on again then it works fine without my PC on, which means it's definitely my PC trying to forward something toward the site because when I normally visit it it displays a page I never uploaded to the server but when I use a different device it shows the exact same error as you described. Run antivirus as well on PC when network is forgotten then try again or if possible, don't use the PC at all if it's the main cause of the problem. I'm using Linux without Antivirus so since I don't really use my PC most times, I just use my phone and everything seems to be fine. You can even try using a different web browser if you don't wanna clear your cookies and browser data from the browser you're using. Using Firefox instead of Chrome has helped me whenever I use the PC when necessarily needed, but do this after restarting the network. You can try updating name servers as well, just as Tyler said because sometimes it could be a DNS Forwarding issue which is mainly on the server and not your computer. Anyway, hope that helped.
