How to open a web server port on EC2 instance

You need to open TCP port 8787 in the ec2 Security Group. Also need to open the same port on the EC2 instance's firewall.

You just need to run command

sudo iptables -A INPUT -p tcp --dport <port_number> -j ACCEPT

You will be allow to access port in AWS Ubuntu

Follow the steps that are described on this answer just instead of using the drop down, type the port (8787) in "port range" an then "Add rule".

Go to the "Network & Security" -> Security Group settings in the left hand navigation

Find the Security Group that your instance is apart of Click on Inbound Rules Use the drop down and add HTTP (port 80) Click Apply and enjoy

You need to configure the security group as stated by cyraxjoe. Along with that you also need to open System port. Steps to open port in windows :-

1. On the Start menu, click Run, type WF.msc, and then click OK.
2. In the Windows Firewall with Advanced Security, in the left pane, right-click Inbound Rules, and then click New Rule in the action pane.
3. In the Rule Type dialog box, select Port, and then click Next.
4. In the Protocol and Ports dialog box, select TCP. Select Specific local ports, and then type the port number , such as 8787 for the default instance. Click Next.
5. In the Action dialog box, select Allow the connection, and then click Next.
6. In the Profile dialog box, select any profiles that describe the computer connection environment when you want to connect , and then click Next.
7. In the Name dialog box, type a name and description for this rule, and then click Finish.

Ref:- Microsoft Docs for port Opening