Swagger, API Gateway using AWS Cloudformation - yaml

Question

I am deploying a API which is mapped to a loadbalancer. I could test the API successfully on the console but while using the invoke link in the stage, I am getting a 403. The ELB is a http end point and the invoke url is https which is normal I would say.
Also if I use the ELB DNS Name, I could get the desired result. Looks like requests are not going through API Gateway.
I am doing all of this using Cloudformation and swagger. Here is the relevant part
EmployeeApi:
Type: AWS::ApiGateway::RestApi
Properties:
BodyS3Location:
Bucket: !Ref S3Bucket
Key: "swagger.yaml"
EmployeeApiDeployment:
Type: AWS::ApiGateway::Deployment
Properties:
RestApiId: !Ref EmployeeApi
EmployeeApiStage:
Type: AWS::ApiGateway::Stage
Properties:
DeploymentId: !Ref EmployeeApiDeployment
RestApiId: !Ref EmployeeApi
StageName: dev
Variables:
employeeELB:
Fn::ImportValue:
!Sub ${NetworkStackName}-ELB
EmployeeApiUsagePlan:
Type: AWS::ApiGateway::UsagePlan
Properties:
ApiStages:
- ApiId: !Ref EmployeeApi
Stage: !Ref EmployeeApiStage
UsagePlanName: Basic
EmployeeApiKey:
Type: AWS::ApiGateway::ApiKey
Properties:
Name: employee-api-key
Enabled: true
StageKeys:
- RestApiId: !Ref EmployeeApi
StageName: !Ref EmployeeApiStage
Relevant part of my swagger file is
swagger: "2.0"
info:
version: 1.0.0
title: employee-service
description: Welcome to API documentation of Employee Service
schemes:
- https
securityDefinitions:
api_key:
type: apiKey
name: x-api-key
in: header
x-amazon-apigateway-request-validators:
RequestValidator:
validateRequestBody: true
validateRequestParameters: true
x-amazon-apigateway-request-validator: RequestValidator
paths:
/employees:
get:
security:
- api_key: []
x-amazon-apigateway-integration:
responses:
default:
statusCode: "200"
uri: http://${stageVariables.employeeELB}/employees
passthroughBehavior: when_no_match
httpMethod: GET
contentHandling: "CONVERT_TO_TEXT"
type: http_proxy