| UNREACHABLE! => { "changed": false, "msg": "Failed to connect to the host via ssh: Invalid multiplex command.", "unreachable": true

Issue

ansible -m ping -i inventory.ini webservers

localhost | UNREACHABLE! => {

    "changed": false,

    "msg": "Failed to connect to the host via ssh: Invalid multiplex command.",

    "unreachable": true

}

Troubleshoot

vim devops.ini

ansible_ssh_common_args='-O StrictHostKeyChecking=no'

#change to

ansible_ssh_common_args='-o StrictHostKeyChecking=no'

Result

ansible -m ping -i devops.ini webservers

localhost | SUCCESS => {

    "ansible_facts": {

        "discovered_interpreter_python": "/usr/bin/python3"

    },

    "changed": false,

    "ping": "pong"

}