Node service can be run on ports such as 8080 and 3000.
However, when running on port 6000, it cannot be accessed. This will happen both locally and on the server. Although it can be solved by changing the port number, if you want to know the reason, please consult the great gods.
First of all, make sure that your 6000 port is occupied by other programs. This is very simple. Use
netstat -nap | grep 6000
The result is,
If it is not occupied, it is probably your Firewall problem. Check your Firewall rules. Generally speaking, first look at the rejection rule, then look at the acceptance rule.