Problems with Ansible connecting to i4600

My playbook:

---

- name: Onboard Playbook  
  hosts: i4600
   gather_facts: false
  vars_files:
      - /home//ansible/playbooks/bigip_vars
  connection: local

  tasks:

    - name: Manage SSHD setting on BIG-IP
      bigip_device_sshd:
        user: "{{ username }}"
        password: "{{ password }}"
        allow: all
        login: enabled
        banner: "enabled"
        banner_text: " {{ banner_text }}"
        server: "{{ inventory_hostname }}"
        validate_certs: no
      delegate_to: localhost

    - name: Configure NTP server on BIG-IP
      bigip_device_ntp:
        server: "{{ inventory_hostname }}"
        user: root
        password: default
        ntp_servers: "{{ ntp_servers }}"
        validate_certs: False
      delegate_to: localhost

    - name: Configure BIG-IP hostname
      bigip_hostname:
        user: "{{ username }}"
        password: "{{ password }}"
        validate_certs: False
        hostname: "{{ hostname }}"
      delegate_to: localhost

    - name: Manage BIG-IP DNS settings
      bigip_device_dns:
        user: "{{ username }}"
        password: "{{ password }}"
        name_servers: "{{ dns_servers }}"
        search: "{{ dns_search_domains }}"
        ip_version: "{{ ip_version }}"
        validate_certs: False
      delegate_to: localhost

My bigip_vars file:

username: 
 - 'root'

password: 
 - 'default'

banner_text: "This computer system and associated networks are intended for the business use of  and its authorized users. The Company's computers and proprietary data and information stored on them remain at all times the property of .  Subject to applicable laws and regulations, users have no right to privacy as to any information transmitted or stored in, by or through any portion of this system."

ntp_servers:
 - '10.12.132.2'
 - '10.12.132.3'

dns_servers:
 - '10.12.59.40'
 - '10.12.59.41'

dns_search_domains:
 - 'local'
 - 'localhost'

ip_version: 4

hostname:
 - 'fna-lb01_ansible'
 - 'fna-lb02_ansible'

item.name: ltm

inventory_hostname:
 - '10.12.118.173'
 - '10.12.118.174'

My Host file:

  LAB Big IP Host file 


[i2600]
10.12.118.171
10.12.118.172

[i4600]
10.12.118.173
10.12.118.174