Making Phone Call from App - href="tel:123"

All of the above things I have implemented,
1. Install whitelist plugin
2. Add "" in config.xml

But in my case, it working in some section and in some case it's not. Then I start debug the issue

Working situation:

<div class="help-text"><a href="tel:{{cn.form.io_mobile_no}}" target="_new">(Direct Call)</a></div>

When click on Direct Call its working in Browser and Android both, in the below case its not working even the browser also.

<div class="list">
    <label class="item item-input item-stacked-label">
        <span class="input-label">Name of Police Station</span>
        <div class="info-wrap"><a href="tel:{{cd.form.complainant_mobile_no}}" target="_new">{{cd.form.complainant_mobile_no}}</a></div>
    </label>
</div>

Now, here is the solution " Just replace label tag with span or div." I don't know why but its working for me. Share here, if any one stuck in the above situation. Thanks.