Cannot open EC2 instance public IPv4 address for Coursera AWS Cloud Technical Essentials Exercise 3

Question

Hello I am working on the AWS Cloud Technical Essentials course on Coursera. While working through exercise 3, I ran into a problem.

Despite following all the steps as instructed when I attempt to open the Public IPv4 address for the EC2 instance (by copy-and-pasting it after http://) the webpage says "This page cannot be reached  refuses to connect. ERR_CONNECTION_REFUSED" even though the instance is running, and has passed both status checks.

The security group has only one inbound security rule of type HTTP and source type ANYWHERE. When creating the instance the following code was placed in the User data box under advanced details:
```
#!/bin/bash -ex
wget https://aws-tc-largeobjects.s3-us-west-2.amazonaws.com/DEV-AWS-MO-GCNv2/FlaskApp.zip
unzip FlaskApp.zip
cd FlaskApp/
yum -y install python3 mysql
pip3 install -r requirements.txt
amazon-linux-extras install epel
yum -y install stress
export PHOTOS_BUCKET=${SUB_PHOTOS_BUCKET}
export AWS_DEFAULT_REGION=
export DYNAMO_MODE=on
FLASK_APP=application.py /usr/local/bin/flask run --host=0.0.0.0 --port=80
```

With  replaced with my region.  
The instance also uses a key-pair with the .pem file downloaded onto my desktop.  
Can anyone help me resolve this issue?

Answer

Hi,

In order to troubleshoot effectively I would suggest to login into your EC2 instance and try to check if your application is working by the running this command:

```
wget http://localhost
```

If your application is actually running you should get back an output line containing

```
HTTP request sent, awaiting response... 200 OK
```

If your application is running I would recommend to double check:
- Security Group
- Network ACL of your Subnets

Answer

Hi,
Looks like i faced with same problem. Have you solved it?

Answer

I am unable to get this exercise to work. I have ssh'd to the ec2 instance and notice that when I enter the following command:

```
$ wget https://aws-tc-largeobjects.s3-eu-north-1.amazonaws.com/DEV-AWS-MO-GCNv2/FlaskApp.zip

```
I get the response:

```
-bash: wget https://aws-tc-largeobjects.s3-eu-north-1.amazonaws.com/DEV-AWS-MO-GCNv2/FlaskApp.zip: No such file or directory

```
Is this why the example doesn't work?

Cannot open EC2 instance public IPv4 address for Coursera AWS Cloud Technical Essentials Exercise 3

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