Workflow activity "Call" & "say" under notify_Call table

[Saurav Bhardwa2]

Hello,
I am working on setting up Twilio. Could someone please help me how to use the Call activity?

Below is the script I am using

var answer = getNumbersToCallAndCallFrom();

/**

 * Function to generate the javascript object containing the

 * number to call and to call from.

 *

 * @returns {{notify_number: *, number_to_call: string}}

 */

function getNumbersToCallAndCallFrom() {

    // generate the result

    return {

        notify_number   : getNotifyNumber(),    // the sys_id of the notify number

        phone_number    : workflow.inputs.u_number,             // the E.164 number to call

source_sys_id   : workflow.inputs.u_sysid,        //Pass current sys_id for source

        source_table    : current.getTableName() //Pass current sys_id for source table

    };

}

/**

 * Function to determine the Notify Number to call from

 *

 * Note, the notify number should always be associated to

 * a Notify Group, and that Notify Group should have (at

 * least) an outbound call workflow configured.

 *

 * @returns {*}

 */

function getNotifyNumber() {

    // if this workflow is running in the context

    // of the call table, use the notify number

    // associated

    //if (current.getTableName() == 'notify_call')

        //return current.notify_number;

    // get the first notify number that has a group

    // configured. THIS SHOULD PROBABLY CHANGE!

    var number = new GlideRecord('notify_number');

    number.get('ba8ac5a51ba93514713762007e4bcb0a');

        return number.getUniqueValue();

}

But I am getting this error "The Notify Number is not part of a Notify Group" in the call activity. 
If anyone has used this activity in the past, please correct me what I am doing wrong