AWS Lambda function can't communicate with EC2 Instance
has the security group 8080 port open to internet?
To connect Lambdas with VPC you can't use the default VPC, you have to create one with a nat gateway. 
EDIT: Only if the Lambda fucntion needs to access to internet and VPC.
On AWS, I created a  new lambda function. I added a role to the lambda that has the policy, AWSLambdaVPCAccessExecutionRole. I placed the lambda in the same VPC as my EC2 instance and made sure the security group assigned to the lambda and EC2 instance have the same default VPC security group created by AWS which allows all traffic within the vpc. On my EC2 instance, I have a tomcat app running on port 8080. I tried to hit the URL by two methods in my lambda function:

Using my load balancer, which has the same assigned security group
Hitting the IP address of the EC2 box with port 8080

Both of these options do not work for the lambda function. I tried it on my local computer and it is fine.
Any suggestions?
Security Group for Inbound

Type = All Traffic
Protocol = All
Port Range = All
Source = Group ID of Security Group