VNC Timed out waiting for a response from the computer

Recently in Tencent cloud server ECS The graphic interface and VNC Server, Reference resources ：Ubuntu18.0 Install the remote desktop server software VNC Server
But when connecting, it prompts ：VNC Timed out waiting for a response from the computer

First try to set up a security group on the website to open the port

First, the security group is created , Reference resources ： Cloud server ECS> Security > Security group > Create security groups

Not after trying , Still not connected ;

terms of settlement

sudo /sbin/iptables -I INPUT 1 -p TCP --dport 5901:5910 -j ACCEPT
# Or modify the file directly /etc/sysconfig/iptables file , Add a row ：
 -A INPUT -p tcp -m state --state NEW -m tcp --dport 5901:5910 -j ACCEPT
# restart iptables service ：
 service iptables restart
# without iptables.service file , Use yum Install it. ：yum install iptables-services
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 author ： Diligent man  
 source ：CSDN 
 original text ：https://blog.csdn.net/jisuanji_wjfioj/article/details/78257729 
 Copyright notice ： This article is an original blog article , Please attach a link to the blog post ！

So I executed the following instructions , The firewall doesn't need to be restarted , I didn't do it flush privileges, Reuse VNC Client one connection , Found a connection .

sudo /sbin/iptables -I INPUT 1 -p TCP --dport 5901:5910 -j ACCEPT

Reference article