I am not being able to ssh into EC2 after creation in ansible

[suyesh bhandari]

I am new to ansible and trying to create EC2 and i have several other tasks to perform. here is the code,

- name: Create a Dataloading environment

  hosts: localhost

  gather_facts: False

  vars:

    key_name: sims-admin

    instance_type: t2.micro

    image: ami-e86f35ff

    region: us-east-1

  tasks:

    - name: Provision EC2 instances

      ec2:

        key_name: "{{ key_name }}"

        instance_type: "{{ instance_type }}"

        image: "{{ image }}"

        wait: true

        exact_count: 1

        region: "{{ region }}"

        count_tag:

          Name: CounttagANSIBLEDataloading

        instance_tags:

          Name: ANSIBLEDataloading

      register: ec2

    - name: Add new instance to host group

      add_host: hostname={{ item.public_ip }} groupname=amazon_ec2

      with_items: '{{ec2.instances}}'

    - name: Wait for the instances to boot by checking the ssh port

      wait_for: host={{item.public_dns_name}} port=22 delay=60 timeout=320 state=started

      with_items: '{{ec2.instances}}'

- name: Configure instance

  hosts: amazon_ec2

  become: True

  gather_facts: True

  tasks:

    - name: Get the latest updates for instance

      apt:

        update_cache: yes

        upgrade: dist

It works until breathing room but fails in configure instance. I get the error saying

fatal: [54.145.185.81]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect to the host via ssh.", "unreachable": true}

At first i was struggling to even ssh to come up to work. I finally got it work somehow but now the configure instance is not working. i am using ansible 2 on mac. 

I am not sure why Configure instance fails? how am i supposed to login to ec2 in ansible? i have the key.pem in ~/.ssh/key.pem 

Please help me with explanation and maybe links to relevant links. Alsthough i have been to several links and since my basic understanding on ansible is low i dont quite get it.