What could be the reason behind "ERR_CONNECTION_TIMED_OUT"?

I am using (airtel xstream fiber) connection and trying to do port forwarding. I forwarded port 3000 of wan and direct it to my system ip address 192.168.1.2 on port 3001.

Node server is running on my system on port 3001. And I can access my hello world website locally using 192.168.1.2:3001. But when I am trying to access using public ip, it show this error code "ERR_CONNECTION_TIMED_OUT".

Also, I found my router port 3001 is open using online port checking tool/website.

So, Can anyone please tell what could be reason behind this ? Is this the problem with windows.

No there is no need for static IP to be access server remotely. As of now, What I see is airtel allocates new ip every 24 hr or when router got disconnected. To access your server remotely you can do two things. First one is more secured.

1. Change Primary IP adress of your airtel router and use Portforwarding so that its port 80 will be free for you.
2. Enable DMZ and point it to your local server IP. [192.168.X.X]. In this case all of your ports of the device are exposed to internet. If you want to be secure. Make sure add another router between server and airtel router and enable port forwarding.

But in this case there is a catch, When you try to access your local website using public ip (which you can see on google search) it will redirect you to airtel router panel. But when you try to access it using other device (not server otherwise server will get disconnected) connected to internet using other network(other that your current airtel router like JIO sim, Airtel Sim, etc), It will work excellently.

To get rid of dynamic ip use no-ip services. Its website will help you more. Basically, It is dynamic dns server where you will get free domain. That will get update regularly while its service running on your system. To use other dns provider service like godaddy you must need an static ip.