I am assuming you have encountered this error when using Shadowsocks and have stumbled upon this website upon Googling it. :)
I have also faced this issue and spent countless hours trying to find out what went wrong.
Step 1: Check your Shadowsocks server’s IPtables (if you’re running Fedora, check Firewalld too)
Have you added an exception rule for IPtables? If not, you should run the following commands:
/sbin/iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport SERVER_PORT_NUMBER -j ACCEPT
Replace SERVER_PORT_NUMBER with the port number of your Shadowsocks server.
If you would like to save the hassle of doing so, you can simply turn off IPtables with the following commands :
service iptables stop
chkconfig iptables off
By now it should be working, however, if you’re still facing this error, proceed to step 2
Step 2: Run Shadowsocks client as Administrator
If you’re running windows, you need to always run Shadowsocks client as an administrator or else it will not work.
If you’re still facing this issue, please let me know through the comments below. Thank you and I hope that this has helped you a lot! :)