High Sierra: Can't connect to a xampp server running on another machine after upgrading macOS I have a Xampp web server running on another computer in the local network and my Mac can no longer access it after updating to High Sierra.

All other devices I have in the same Wi-Fi network connect to the web server using the server computer's IP address without any issues.

The only thing that changed, as far as I know, is that the Mac was updated to High Sierra. 

Any guesses?
I am assuming you are using SSL with certificate that is SHA-1 signed, which was still allowed (with a warning) in macOS Sierra but in macOS High Sierra the connections will fail. I suggest you move to SHA-256 signed certificates for increased security and to avoid connection failures.

Source: Apple HT207459