Jupyter notebook on AWS gives an error when connecting to Kernel

I have created an EC2 instance with port 7180/443 open. No proxy is set. When opening on browser(multiple browsers were tried), it gives the error:

> A connection to the notebook server could not be established. The notebook will continue trying to reconnect. Check your network connection or notebook server configuration.

The log in the terminal shows:
```
[I 14:43:09.777 NotebookApp] The Jupyter Notebook is running at: http://0.0.0.0:7180/
[I 14:43:09.777 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[I 14:43:17.596 NotebookApp] Creating new notebook in
[I 14:43:18.412 NotebookApp] Kernel started: 045de2f8-01a1-4050-bd61-94c84757c9f1
```

I am able to use python directly on the terminal. But the kernel is not working. Tried both python 2 and 3.. So, the kernel starts but not able to connect to it.

No source file or test is named. Start by reproducing the EC2 setup using the reported ports 7180 and 443, then inspect the browser connection errors alongside the NotebookApp and kernel logs. Done means the browser establishes a connection to the started kernel without repeated reconnect errors.

Written by the indexing model from the issue text.