[Answer]-Django Link not working in for loop

Per MDN a TR may only contain a mixture of TD or TH elements.

Change your template to compensate for this. (also it appears you likely have a typo and meant t.completed)

Possibly:

<h1 id="title">Joe's Basic Task List</h1>
<table id="taskTable">
{% for t in taskList %}
    <tr>
    {%if t.completed == 1%}
        <td><div class="btn active"><i class="fa fa-check"></i></div></t    d>
    {%else%}
        <td><div class="btn"><i class="fa fa-check"></i></div></td>
    {%endif%}
        <td class="tableText">
            <a href="{% url 'tasks:detail' t.id%}">{{t.task}}</a>
            <input type="hidden" name="id" value="{{t.id}}"/>
        </td>
    </tr> 
{% endfor %}
</table>

Also consider changing the div’s to span or putting the styles directly on the td. Both display as block elements (well the td is a table-cell display, but will behave similarly as a block level element with styling).

Having divs nested inside of a td just seems wrong as you don’t really need it for positioning / styling purposes.